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4 Best PDF Annotator and Markup Apps for All Platforms

by Gaurav Bidasaria

There are PDF editors available for every platform and they come in all shapes and sizes. The thing is that not all of us are looking for a PDF editor. A lot of us simply need a PDF annotator and markup tool that will let us highlight important parts or add a comment/thoughts. This is really useful when you are re-reading the PDF at a later point. You don’t have to go through the whole thing again and waste your valuable time.

Instead of using paid PDF editors that offer advanced features that you don’t really need or could care less about, it is better to get a PDF annotator and markup tool that will help you with just that, mark, annotate, and comment. Whether you are using an Android, iPad, Windows or Mac, we will cover at least one app for each. Let’s begin.

Best PDF Annotator and Markup Apps

1. PDF Annotator and Marker for Android

First up in the list is the Xodo PDF Reader and Editor, which is one of the highest rated, free PDF annotator and marker apps on the Play Store. The reason why Xodo made it to this list is because the UI is not only functional but the app comes with some cool features.

With Xodo, annotating and adding comments is as easy as long-tapping anywhere on the page. A small box will pop up with options like add comments, draw shapes like squares, circles, and lines, highlight text using color, underline or strikeout or simply type your thoughts. Where Xodo makes things interesting is that all these presets are customizable so you can change color, font type and size, thickness and even opacity while using annotating tools.

PDF Annotator and Marker for Android 1

Finally, you can add signatures to documents or fill-in forms right on your Android smartphone. There is an option to add custom images to pages (think watermarks) and even stamp them if that is what your boss wants you to do.

If you select a piece of text, Xodo will offer you to translate that text in other languages using Google Translate or find its meaning using the built-in dictionary. Very useful when reading books where you often find words that are out of your vocabulary box.

For people who like to listen, not read, while still needing to annotate their PDF files, Xodo comes with a speech-to-text feature that will read the selected word/s out loud. Very helpful when you don’t know how a certain word is pronounced.

PDF Annotator and Marker for Android 2

Xodo will connect with other cloud storage service providers like Dropbox and Google Drive. You can then use it to annotate and mark PDFs in collaboration with others in real time. Useful for students working on a project.


  • Connect with cloud storage apps
  • Select font type, size, color
  • Insert or draw shapes, sizes, objects, images, links
  • Sign, fill-in, stamp forms, highlight, bookmark, comment
  • Dictionary and translator


  • None

Download Xodo PDF Reader & Editor (Free)

2. Best PDF Annotation App for iPad

At this point, I would like to remind you that Xodo, that we discussed above for Android, is also available on iTunes and remains one of the best PDF annotator and marker apps. But, iOS is home to many other PDF annotators and one of them is PDF Expert by Readdle. When you use the word “expert” in the name, you immediately set a high standard for yourself. PDF Expert won’t disappoint.

PDF Annotator and Markup Apps for ios 1

Apart from the usual features that you would expect in a robust PDF annotator like adding notes and comments, choosing font type and color, highlight, and filling and signing forms, PDF Expert offers custom stamps. Editors will be happy to know that you can now create commonly used stamps to annotate and give feedback.

Apple introduced the Apple Pencil in the new iPad lineup and PDF Expert takes full advantage of it. You can use Apple Pencil or your fingers to draw on pages and even images. Finally, PDF Expert will connect and sync data from all popular cloud storage platforms. With security in mind, PDF Expert has an option to not only password-protect your files but also use Apple’s Data Protection feature to encrypt the files and data within.

PDF Expert will cost you $9.99 and if you subscribe with an in-app purchase, you get additional features like the ability to edit full text and images, redact sensitive text, change opacity, and add links.

PDF Annotator and Markup Apps for ios 2

Note that PDF Expert is also available for MacBooks which will bring a lot of consistency between UI if you frequently find yourself switching between iPhone, iPad, and MacBook.


  • Supports cloud storage
  • Select font type, size, color
  • Reduce PDF file size using compression
  • Insert or draw shapes, sizes, objects, images, links
  • Sign, fill-in, stamp forms, highlight, bookmark, comment


  • Can be expensive for some users
  • Can’t add links without subscription
  • Dictionary and translator missing

Download PDF Expert ($9.99)

3. PDF Annotator and Marker for Windows

Acrobat created the PDF standard and its PDF reader is not only free, but also pretty powerful. Features like adding notes, comments, changing font types, size, and color are all there. You can easily add stamps or create and upload your own customized one. Signing documents and filling forms were never so easy and accurate.

PDF Annotator and Markup Apps for ios 3

Not everything is free in the Adobe world. While highlighting notes, attaching files, recording audio is free, you will have to subscribe to the DC Pro plan, which can be expensive at $15/mon, to unlock advanced editing features like creating and editing PDF Files. Under Annotations, you will see a number of shapes that you can insert but I couldn’t find a way to add my own. You can, however, play around with its properties to change size, color, and more by right-clicking on it.

Finally, Adobe Acrobat DC Reader comes with a built-in converter to convert PDF files to popular MS Office formats like Word and Excel.

Note that Adobe will ask you to download and install McAfee antivirus which is ticked by default.


  • Easy to use
  • Fill-in, sign PDFs
  • Add notes, comments, shapes, stamps
  • Attach files, record audio
  • Control font type, size, color,
  • Convert to MS Office formats


  • The subscription model is expensive, suitable for enterprise users only

Download Adobe Acrobat Reader DC (Free)

4. PDF Annotator and Marker for macOS

Most big software and apps are cross-platform compatible which means all the features we saw above in Adobe Reader DC for Windows are also available for the macOS platform. It is pretty much the default way to read and annotate PDF files on the Mac platform.

If you are willing to pay for and need advanced features, you should look at PDFelement 6 Pro.

PDF Annotator and Markup Apps for mac 4

PDFelement 6 Pro is not just a reader and an annotator but a full-fledged PDF editor. You can easily add and edit both text and images in pages. Signing documents can be done using an image or by drawing using hand gestures. Regular font and text features like type, size, color, strike-through and adding notes and comments are pretty much standard.

One notable feature is the OCR using which you can convert scanned images into editable PDF files. Good for students and professionals alike.

Honorary mention will include Preview which is free and comes pre-installed on all MacBooks. With Preview, it is easy to manage font type, size, and color, and you can use it to fill forms. During tests, Preview found it a little difficult to locate the correct boxes while filling info. Under the Tools menu, you will find Annotate which will help you add a speech bubble to add comments or maybe notes. Finally, you can sign docs and add/remove pages. Preview is good enough for most people but if you need more features, and easy to use UI, there are far better options available on Macs.

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Why not Acrobat DC Pro? Because for the same price, you get more options and features with PDF Element 6 Pro.


  • Add, edit images, text, links
  • OCR for scanned images to PDF
  • Font type, size, color, etc.
  • Sign, fill forms
  • Comments, notes, bookmarks
  • Convert or export to MS Office formats


  • Subscription model

Download PDFelement 6 Pro ($59.95)

Which is the best PDF Annotator App?

As you can see, there is some overlap. Quite a few apps are available on more than one platform and that is the sign of a good app. So you can use them interchangeably however you like. Adobe Reader DC is available on both Windows and Mac plus they also have mobile apps. Xodo PDF Editor is available on both iOS and Android mobile platforms. Similarly, PDFelement 6 Pro has covered both the major OSes. You can choose any depending on your personal use case scenario and liking.

Also Read: 8 Best PDF Editor for Ubuntu And Other Linux Distro

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