How to Annotate PDF's - The Best Tools for Editing and Marking Up PDF's Reviewed (updated August 2021)

A quick search on Google for "Annotate PDF" or "Edit PDF" will return a ton of tools. And checking search volume on Google Adwords it's clearly an ongoing pain point for people. But the need is nuanced in that one person looking for a way to annotate PDF's may differ greatly from the next user searching for the same thing. To this end, we've created an article that breaks down the common PDF annotation use cases and compares many popular solutions to this problem.

First, let's start with why Adobe Acrobat is not your only option and more importantly why it's the worst solution. Sure, Acrobat has some benefits when creating PDF's from scratch, but honestly it's a pain in the butt to do some really simple things, like adding arrows or text callouts, or blurring content. And of course, it's expensive. So let's review some of the many alternative tools for annotating and editing PDF's, some of which are free and ultra simple to use.

So here are the use cases and best solutions for each. If you want to just see the solution breakdown table comparing features, price and use cases, scroll down towards the end of this article.

Use Case #1 - Add Markup Like Arrows, Text, Shapes, Redaction, Highlight, Pen Tools, etc.

This need appears to be the most common. You need to add some basic markup on top of a PDF like circling some text and suggesting an edit. Or adding arrows to callout a certain section. Or redacting some content with blur or an overlay box. Or maybe just adding free-form writing on top of the PDF. For this use case the key is ease of use, speed and share-ability. Most of the tools covered in this article accomplish this, but they also do a lot more, can be cost prohibitive, overly complex and in some cases just outright janky.

Best - Markup Hero: If all you need is to add arrows, text, shapes, redaction, highlights, pen markup and want the fastest, easiest to use, lowest cost (free) tool to do this, then Markup Hero is the winner by far.

Use Case #2 - Adding Signature Blocks and Signing PDF's

This need is the second most common and often goes hand in hand with use case #1 above. The idea is that you need a quick and easy way to digitally sign a document and share it with someone. Again, just about every solution in this article offers this capability, but most of them make this much more cumbersome than needed. In a lot of cases you'll have to download a software application, install it, configure it and then actually sign-up or even pay to try it. For this use case, web based is optimal because there is no delay. And you really don't want to signup or pay just to try it out.

Best - Markup Hero: If you need a fast way to add your signature or sign off on a contract, form, design brief or other type of PDF then look no further than Markup Hero. It's fast. Easy. Free. It's a no hassle, no bloat solution for adding signature blocks.

Use Case #3 - Creating Fillable PDF Forms

The need to create a form on top of an existing PDF is a fairly common use case but more of a special need situation. Of course you can do this in Acrobat, but it's kinda a pain and Acrobat is expensive. Many of the tools listed here offer the ability to add fillable form fields, but they are not all created equal. If this is all you need to do, then the solution of choice is PDF Filler.

Best - PDF Filler: If you need to make actual fillable form fields on your PDF, this tool makes it pretty easy. You can drop in text boxes quickly and collect the into a single folder for quick access.

Use Case #4 - Add, Remove and Re-order Pages in PDF's

Unlike the previous use cases, this one is actually really easy with Adobe Acrobat, but if this is all you need to do, it's not even close to worth the price. It's surprising this is such a common need but turns out it is. Often this need includes combining PDF's, adding other file types like images as pages within the PDF and probably exporting back to original PDF format.

Best - PDF Sam: Again PDF Filler is pretty quick and easy for this. You can insert pages, merge, rearrange, rotate, split and more.

Use Case #5 - Sharing, Exporting and Converting PDF's

Finally, this use case is a bit more complex. There are various needs addressed with exporting and sharing your edited PDF. For many people, it's simply sending a link to someone so they can view the annotated PDF. In other cases it's actually downloading the PDF in original form and sending it via email or Slack. Or perhaps you need to convert your PDF to another format like images, HTML or Microsoft Word for example or build a PDF flip book (which you can create using for example Publuu's flip book maker). So I've broken down the best solutions for each of these three needs.

Best for Sharing a Link - Markup Hero: If you need a fast way to add your signature or sign off on a contract, form, design brief or other type of PDF then look no further than Markup Hero. It's fast. Easy. Free. It's a no hassle, no bloat solution for adding signature blocks.

Best for Exporting - Sejda: This tool is a little complicated and may be more than you need, but does offer nice exporting options back to original PDF format.

Best for Conversion - Small PDF: This tool gives you some quick and easy ways to get your PDF into other formats like Word, JPG, Excel, etc.

Below I've created a table showing various use cases, pricing and ease of use for 16 PDF annotator and editing solutions. One thing you'll notice is a column called "janky factor".  In the software world we often use the term "janky" to describe a piece of software with poor UX and awful usability. Often janky tools are also buggy and/or laggy which make using them very frustrating. We've included a janky factor rating to give you a sense of how clean and user friendly and reliable each of the solutions below are.

1. LOW - Looks great, works great, simple and clean UX
2. MID - Looks good, can be confusing and hard to use
3. HIGH - Bad UX, not clear how it works, can be frustrating

Hopefully this was helpful. We'll do our best to keep this updated as the landscape for alternative PDF editor and annotation tools changes regularly.

Need something different, or custom? Consider building your own PDF tool and use a library like Docotic.Pdf from Bit Miracle for .NET/C# which is incidentally what we use at Markup Hero; it's solid.