10 Free PDF Annotation Apps for Android & iOS

Need to mark the important points while reading a document? This article has you covered!

There are plenty of free PDF annotation apps for Android & iOS that lets you mark the important paragraphs, write notes, and all that. These apps are actual productivity boosters, especially if you’re using annotation in a collaborative mode!  Plus, the majority of these apps support document editing, so you get a full set of essential tools.

We’ve gathered together the 10 best free apps in that category you may try. Take a look!

Adobe Acrobat Reader

Adobe Acrobat

Could such a list even be full without an Adobe app? Probably not.

Sooth to say, it’s one of the best apps you can use to work with PDF files on the go. It’s an ultimate doc reader that lets you keep, view, and annotate your files wherever you are. You even get to add an e-signature to the docs if you have one. The interface is quite minimalistic and eye-pleasing to not distract you from the file in any way.

The app covers several view modes, so you may rather choose a single page or a scrolling mode. Besides, the doc’s content will automatically reflow to fit the screen, so there won’t be troubles with that. You’ll also get to search within the doc and leave bookmarks.

There’s also a dark mode that not only saves your eyes but the battery as well. Plus, the app lets you set the docs to printing right away if needed. The same goes for sharing — you get to send files via messengers for commenting or viewing. The app will send you activity notifications for all the shared files, so you won’t miss anything

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PDF Reader Pro

pdf reader pro

It’s a PDF app that lets you manage files on the go.

The app runs on a stable mechanism that provides you smooth reading experience and powerful editing tools. This app lets you view and edit several files at the same time which is quite handy and great for multitasking. As for the annotation, the app lets you highlight the words, underline them, add stamps, links, and so on.

You can also write on top of the doc with freehand and add an electronic signature as well. Beyond that, you’ll get to add watermarks to all the official and business files. You’ll also get absolute freedom of action with the organization — you can reorder the pages, delete and add new ones.

The app covers a converting tool that lets you turn JPG, PNG, and other files into PDF. Additionally, you can add password protection to some docs if needed. The app also has a built-in scanner for images, notes, receipts, and all that.

PDF Reader Pro PDF Reader Pro 2


WPS Office

wps expert

Next, we have an all-in-one office suite that lets you access various formats of files.

If you normally work with several formats of docs — this app is your cup of tea. It covers all the commonly-used formats — from PDF to Excel, and even PowerPoint. Herewith, the editing tools are equally powerful for all the formats so no worries about that.

As for the PDF, the app lets you view, edit and share the docs easy as pie. You also get a full complexion of annotation instruments such as a highlighter, a stamper, underlines, and more. Plus, you get to write on top of the text and add an e-signature. There’s also a built-in scanner if needed.

The app also covers plenty of templates for presentations, resumes, and various types of docs (there’s even one for grocery shopping lists). The app comes with a converter that lets you change the doc’s formats in a blink of an eye. Besides, the app syncs with cloud storage services so you can keep all your files safe.

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Foxit PDF

That’s a PDF editor that lets you keep PDF files on hand.

It’s a standard app for the genre with all the classic tools covered. To be more precise, the app lets you view and edit PDFs, comment on them, annotate them, and more. The app also lets you reflow your files and add bookmarks wherever needed.

There’s also a built-in searching engine that lets you search beneath the doc’s content. Plus, there’s a voiceover tool that will read the file out loud for you. The app also supports a tabbed interface, but it’s only available for tabs.

Additionally, the app comes with a collaborative mode that lets you work and docs along with other people. This mode supports annotations, stamps, and comments as well. You can also set activity notifications that will alert you to all the changes within each doc.

Foxit PDF 1 Foxit PDF 2


Google Play Books

Google Play Books

Although you may be surprised to see that app on our list, it actually copes with the main task — opens PDF files and lets you annotate them.

Herewith, the overall concept of this app is slightly different — it’s an e-book reader with audiobook support. The mechanics are simple — you just need to download a book or its audio version to listen to on the go. Once you’ll finish the first book, you’ll start to get personalized recs.

The majority of the books are paid for, but you’ll get to view a free sample before buying. But let’s move to the annotation part. The thing is, this app won’t let you open your docs (you have all the other apps on our list to do that tho). However, you get to annotate books you read by highlighting, underlining, stamping, and more.

You’ll also get to adjust the font type, the text size and alignment, the margins, and more. Plus, you’ll get to leave bookmarks if needed. The app also lets you create custom shelves to organize your book collection.

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PDF Reader

PDF Reader

Next, we have another PDF viewer with a simple UI and controls.

Shortly speaking, this app can cover all your PDF-related needs. For instance, it lets you view docs, annotate them, scan, covert, and sign them on the go. The app also covers a collection of stamps such as approved, sign here, and all that, and you can add custom ones as well.

The app also lets you handwrite on top of the text and even add an electronic signature if you have one. And if you own a tablet you’ll get to open two docs at the same time. Plus, you’ll get to send docs to printing which is quite handy.

Beyond that, there’s a text reflow mode that includes speech conversation. You can also search within the text using keywords or jump to particular pages right away. This app zips and unzips the files automatically, so you won’t need an extra app for that.

PDF Reader 1 PDF Reader 2


Xodo PDF Reader

Xodo PDF

It’s a PDF reader with a fast viewing engine and solid functionality.

The concept of this app is pretty standard — it lets you view, edit, and annotate PDFs on the go. Plus, the app syncs with various cloud services, so you wouldn’t lose any docs. Herewith, all the edits you add in a file will be automatically synced with could service of your choice.

Speaking of the annotating tool, it covers all the basic tools such as a marker, an underliner, a stamper, and all that. The annotation is also available in a collaborative mode if needed. Plus, you can set notifications to alert you on all the changes added to the doc by other users.

Additionally, you get to add bookmarks for future reference. You can also write and type on top of the document and add an e-sign as well. The app lets you work across several docs at the same time, but it’s only for tab owners. Besides, there’s a built-in scanner if needed. The app runs on sub packs, but the majority of essential features are free.

Xodo PDF 1 Xodo PDF 2


Flexcil Notes


This is a note-taking PDF app that lets you edit your files like a pro.

As for the concept, it’s a digital planner that lets you manage your memo, read and edit docs on the go. The main goal of this app is to boost your productivity, so all the tools are easy to use and fast-working. The annotating tool lets you highlight text and images, underline words, and use gestures for note-making.

Along with that, the app comes with a built-in pen engine that lets you write on top of the text. Herewith, the pen is vector-based, so it’s not a problem to get nice handwriting. The color range of the pen is huge, and you can change the size and the brush.

The app also covers several viewing modes, so you could read your PDFs with maximum comfort. The text will automatically adjust to your screen orientation so no worries about that. Plus, the app works in multitasking mode on tabs which is great.

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PDF Viewer Pro

pdf viewer pro

It’s a PDF viewer that lets you manage your files easy as pie.

If you need to get maximum productivity out of document work — this app is for you. The app covers a collaborative mode and lets you work on several files at the same time. Besides, all the essential tools are covered — you get to view and annotate your docs, and share them at any time.

Thereby, the app syncs to a cloud service, so you can keep your docs safe and sound. There’s also a built-in searching engine that lets you search within the text using keywords. The annotating tool lets you highlight the text, leave comments, and write on top of the text.

As for the reading part, the app does the job pretty well. You’ll get several viewing modes, the ability to skip to a specific page, and a zooming tool as well. You can also change the theme of the app if you’re not into the original one (there are 12 options to choose from).

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You may also check: 6 Free PDF Audio Reader Apps for Android & iOS



And lastly, we have a simple PDF reader app that is perfect for superficial work.

In the first place, this is a light version of an original app that is fully dedicated to reading and annotating. Thus, if you have to work with docs on a daily basis and may need to edit some — go for another app. Herewith, the app supports form filling so keep that in mind.

The UI is nothing special — it’s not bad but pretty standard (which is a question of taste). The reading aspect could cover all your needs as there are several viewing modes, and you get to adjust the scrolling method. Plus, you can zoom the doc, skip to specific pages, and add bookmarks.

The annotating tool lets you highlight the text and add hyperlinks. Plus, the toolbar comes with a search engine, so you could search within the text. And if your file has a table of contents it will automatically appear in the app as well.



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Anne Novikova
Enjoy finding leading apps of all kinds and share them with the world. An iOS user with an interest to all gadgets that make life easier and more fun.