What Are the Different Types of PDF Files? (Searchable, Scanned, Tagged, PDF/A)

The main types of PDF files are searchable PDFs (with real, selectable text), scanned or image-only PDFs (pictures of pages with no underlying text), tagged PDFs (structured for accessibility and screen readers), and PDF/A (a locked-down archival format built to stay readable for decades). Most documents you handle fall into one of these groups, and many overlap.

That overlap is the part nobody explains. A single file can be scanned and searchable, or searchable and tagged, or saved as PDF/A on top of all that. "PDF" is really a container, and what sits inside it decides whether you can copy the text, run a screen reader over it, or trust it to open correctly years from now. Once you can spot which kind you're holding, a lot of everyday frustration, like text you can't select or a file your company keeps rejecting, suddenly makes sense.

Key takeaways

• A PDF is a container; the types of PDF files describe what's inside, not the file extension.
• Searchable PDFs have real text you can select, copy, and search. Scanned (image-only) PDFs are just pictures of pages.
• Tagged PDFs add an invisible structure layer so screen readers and reflow tools understand headings, lists, and reading order.
• PDF/A is an archival variant designed to look the same and stay openable far into the future.
• These categories overlap: one file can be scanned, then made searchable, then tagged, then saved as PDF/A.
• Knowing the type tells you whether you can edit, search, or rely on the document, before you waste time fighting it.

A quick history, so the categories make sense

PDF began at Adobe in the early 1990s under a project John Warnock nicknamed "Camelot." Adobe released PDF 1.0 in 1993 with one goal: a document should look identical on any computer, printer, or screen. For years it stayed a proprietary Adobe format, then in 2008 it became an open international standard, ISO 32000-1, free for anyone to implement.

That history matters because the different "types" of PDF arrived in waves. The original format cared mostly about looking right. Later, people needed PDFs that machines could read (searchable text), that assistive technology could understand (tagged structure), and that institutions could trust to survive (PDF/A). Each type solves a different problem, which is exactly why no single one is "best."

The four main types of PDF files

Think of these as the categories that cover almost everything you'll run into. We'll go through each one: how to recognize it, what it's good at, and when it's the right choice.

1. Searchable PDFs (text-based)

A searchable PDF contains actual text characters underneath what you see on screen. When you press Ctrl+F (or Cmd+F on a Mac) and look for a word, it gets found. You can highlight a sentence, copy it, and paste it somewhere else, and the words come along intact.

Most PDFs created digitally are searchable by default. When you export from Word, Google Docs, a web browser, or design software, the text you typed stays as text rather than being flattened into a picture. These are the friendliest files to work with: you can edit them, pull quotes out of them, and reflow them with far less effort.

There's a subtle catch worth knowing. A PDF can look like crisp text and still not be searchable, for example if it was made by "printing to PDF" from a scan. So the only reliable test is to actually try selecting and searching, not to judge by how sharp the letters look.

How to tell: open the file, drag your cursor across a line of text, and run a search. If the cursor highlights individual words and search finds them, it's searchable.

Best for: reports, contracts, invoices, ebooks, anything you or others will need to read, search, edit, or copy from.

2. Scanned (image-only) PDFs

A scanned PDF is a picture. When you run a paper document through a scanner or snap a photo with a phone app, you usually get a PDF where each page is a flat image. It looks like a document, but there are no real text characters inside, just pixels arranged to resemble letters.

The giveaway is simple: you can't select the words, and search finds nothing, even though you can plainly read the page with your own eyes. Trying to copy "text" either grabs nothing or grabs the whole page as one image. These files also tend to be larger than their searchable equivalents, because a photo of a page carries far more data than the handful of characters it represents.

This is the single most common source of "why can't I copy this?" confusion. The fix is OCR (optical character recognition): software reads the image, recognizes the shapes as letters, and adds an invisible text layer behind the picture, turning a scanned PDF into a searchable one. OCR isn't perfect, faint scans, handwriting, or odd fonts can produce mistakes, but it's good enough that most scanned business documents become fully searchable. If you want the full breakdown of how the two differ and how OCR bridges them, see our guide on searchable PDF vs image-only PDF.

How to tell: the page reads fine to your eyes, but nothing is selectable and search comes up empty.

Best for: capturing signed paper, receipts, ID documents, or any physical original. Just run OCR afterward if you'll ever need to search or edit it.

3. Tagged PDFs (accessible)

A tagged PDF carries an invisible map of its own structure. Tags label which text is a heading, which is a paragraph, which is a list item, what order things should be read in, and what alternative text an image should announce. None of this changes how the page looks; it changes how machines interpret it.

This matters most for accessibility. A screen reader used by someone who is blind or has low vision relies on tags to read a document in a sensible order and to describe images rather than skipping them or reading raw file names. Tags also let content "reflow," so it resizes cleanly on a small phone screen instead of forcing you to pinch and pan. Many governments, schools, and large companies now require tagged, accessible PDFs, often to meet standards like PDF/UA or WCAG.

A file can be searchable but not tagged. Searchable means the text exists; tagged means the text is organized and labeled so its meaning is clear. A wall of correctly spelled, fully searchable text with no tags can still be a maze for a screen reader. For the deeper why-and-how, read what a tagged PDF is and why it matters for accessibility.

How to tell: this one is harder to eyeball. In a full-featured PDF reader you can open a "Tags" panel or run an accessibility check; if structure tags are present, the file is tagged.

Best for: public-facing documents, government and education materials, and anything that must be legally accessible.

4. PDF/A (archival)

PDF/A is a stricter, standardized version of PDF designed for long-term preservation. Its whole purpose is that a document opened decades from now looks and reads exactly as it does today. To guarantee that, PDF/A bakes everything the file needs inside the file: all fonts are embedded, colors are precisely defined with a color profile, and features that could break or behave unpredictably over time, external links to other files, audio, video, JavaScript, and encryption, are forbidden.

You'll meet PDF/A when dealing with courts, government filings, libraries, regulated industries, and corporate records retention. Many of these systems reject a regular PDF and accept only PDF/A. There are sub-levels (such as PDF/A-1, PDF/A-2, and PDF/A-3) and conformance levels (notably "a" for fully accessible and tagged, and "b" for basic visual reproduction), and a system will usually tell you which one it needs. The everyday takeaway stays the same: PDF/A trades flexibility for permanence and self-containment.

How to tell: many readers show a banner saying the file conforms to PDF/A, or you'll see it noted in the document's properties or compliance information.

Best for: archiving, legal filing, official records, and anything you must keep readable for many years.

Comparison table: the four types at a glance

Notice the columns don't crown a winner. A scanned PDF isn't "worse" than PDF/A; they exist for different jobs. The right format is the one that matches what you need the document to do.

When to use each type

• Sharing a document people will read and quote from? A standard searchable PDF is ideal: small, editable, and copy-friendly.
• Digitizing paper? You'll get a scanned PDF; add OCR if anyone needs to search or edit it later.
• Publishing anything the public or your employees must be able to access with assistive tech? Make it a tagged, accessible PDF.
• Filing with a court, archive, or compliance system? Use PDF/A, and confirm which sub-level and conformance level they require.
• Building an official record you'll keep for a decade or more? PDF/A again, because self-containment is the whole point.

The honest answer is that most real documents are layered. A government form might be searchable, tagged, and PDF/A all at once. That's not a contradiction, it's good document hygiene: each layer adds a capability the others don't cover.

Two more distinctions worth knowing

The four types above describe a file's purpose. Two other distinctions describe its contents and behavior, and they're worth a quick mention because people often lump them in with the four main types.

Vector vs raster content

Inside any PDF, graphics are stored either as vectors (math-defined shapes and lines that stay crisp at any zoom) or raster images (grids of pixels that blur when enlarged). A logo drawn as a vector stays razor-sharp when you zoom to 400%; a photo is raster and softens as you push in. A scanned PDF is essentially all raster. This affects print quality, file size, and how well something edits or scales. We cover it fully in vector vs raster PDFs and why the difference matters.

Static vs interactive (fillable forms)

Some PDFs are static, just text and images to read. Others are interactive, with form fields you can type into, checkboxes you can tick, dropdowns, and buttons. A fillable tax form or job application is an interactive PDF. This is a separate axis from searchable or scanned: an interactive form is usually built on searchable text but adds clickable fields on top.

How to handle any PDF type you receive

You rarely get to choose the type of PDF someone sends you, so the practical skill is converting between them. A scanned receipt can be made searchable with OCR. A flat document can be tagged for accessibility. A regular PDF can be re-saved as PDF/A for filing. And in many cases you just need to make a quick correction without changing the format at all.

You can do a lot of this in your browser. With an online tool like our online PDF editor, you can open a file, edit text, add or fix content, and export it in the form you actually need, all processed on the server rather than requiring desktop software. Your file is handled to perform the task you asked for and isn't kept around long-term afterward.

FAQ

What are the main types of PDF?

The main types are searchable PDFs (real, selectable text), scanned or image-only PDFs (pictures of pages with no underlying text), tagged PDFs (structured for accessibility and screen readers), and PDF/A (an archival format built to stay readable long-term). These categories often overlap, so a single document can belong to more than one at once, such as a scanned form that has been made searchable and then tagged.

How do I know if my PDF is searchable or scanned?

Open the file and try to select a line of text with your cursor, then run a search (Ctrl+F or Cmd+F) for a word you can see on the page. If the words highlight individually and search finds them, it's a searchable PDF. If you can read the page but nothing is selectable and search returns nothing, it's a scanned, image-only PDF that would need OCR to become searchable.

Is PDF/A better than a regular PDF?

Neither is universally better; they serve different goals. PDF/A is built for long-term preservation, so it embeds all fonts and bans features like external links, video, and encryption to keep the file self-contained. A regular PDF is more flexible and supports those interactive features, which makes it the better choice for everyday sharing. Use PDF/A only when archiving or filing actually requires it.

Can a single PDF be more than one type?

Yes, and most well-made documents are. The categories describe different layers, not mutually exclusive boxes. A document can start as a scan, gain a searchable text layer through OCR, receive accessibility tags, and finally be saved as PDF/A. Each step adds capability without removing the others.

What is a tagged PDF and do I need one?

A tagged PDF includes an invisible structure layer that labels headings, lists, reading order, and image descriptions so screen readers and reflow tools can interpret the document correctly. You need one whenever a document must be accessible to people using assistive technology, which is often a legal requirement for government, education, and many corporate materials. For internal or personal files, tagging is helpful but usually optional.

How do I make a scanned PDF searchable?

Run it through OCR (optical character recognition), which reads the image of each page and adds an invisible text layer behind the picture. The page still looks identical, but now you can select, copy, and search the text. Many PDF tools include OCR, after which a scanned, image-only file behaves like a normal searchable PDF.