PDFs are light, portable and can support a variety of document styles, from text-heavy manuals to highly image-based documents such as ebooks and comics. Form-fillable documents can also be used as official forms and documents. The best PDF reader apps do more then just open files, providing a variety of navigation, annotation, and cloud storage functions to provide a full spectrum of document features. Check out our favorite PDF reader apps for Android and iOS devices. (Image Credit: dennizn/Shutterstock)
The biggest thing that Adobe Reader (Android, iOS) has going for it is that everything just works smoothly, supporting form-fillable and DRM and password-protected PDFs while offering a variety of view modes, from your classic vertical scroll to a two page facing view that looks great in landscape mode. Adobe Reader includes text reflow, contextual search, bookmarks and hyperlink support, as well as annotation and electronic signature support. Users who sign up to a free Adobe Document Cloud account can share and sync documents online, with features like PDF editing and creation available as in-app purchases or through subscription.
The mobile version of the popular desktop tool, Foxit Mobile PDF (Android, iOS) is another good choice for a PDF reader app for your mobile device. On the display end, Foxit handles normal and password protected PDFs, with support for document and user bookmarks. Annotation options let you highlight, underline or strike through text. You also can add sticky notes text boxes, or even draw freehand on the document. Text reflow allows you to read comfortably even on a small smartphone screen. Cloud support lets you upload and download PDFs from popular storage providers. Foxit has also introduced a new ConnectedPDF feature for collaborative work, annotations, comments and edits on a team's files.
Xodo PDF Reader (Android, iOS) might not have the big name recall of Acrobat Reader or Foxit, but it still offers a nice multi-platform reader app that includes a variety of reading modes along with organization and cloud storage tools plus productivity extras like annotations and electronic signatures. Users can open and edit their local PDF files; access PDFs from their Dropbox, Google Drive and OneDrive; or use the proprietary Xodo Connect platform to share and annotate PDFs over a web browser. That said, the mobile reader would be improved with a better design and layout, as features like the menu bars can use up a large amount of screen space and obscure pages, making Xodo somewhat clunky to use.
Another PDF reader to check out is Bookari (Android, iOS). Formerly known as Mantano Reader, it supports EPUB and PDF formats (including Adobe DRM support). Bookari features a customizable and feature-packed reader, with a variety of features such as reader themes, a night mode, text search, annotation and a pinnable navigation panel to let you easily jump between chapters, bookmarks and pages. The $4.99 paid version of the app delivers additional features, and a premium subscription to Mantano Cloud adds support for library and reading progress syncing across devices. It might not be as snappy as more focused PDF readers, but Bookari makes for a nice all-in-one for your EPUB and PDF needs.
Google Play Books (Android, iOS) is another app worth considering for its cloud storage functions. You can upload your own PDF & EPUB files into your Play Books library for cross-device ease of reading, though if you do most of your PDF reading away from a wireless signal, that may be an issue. In addition to cloud storage features, you can also access Play Books' marketplace, as well as customize the reader view for ease of use. Text highlighting, a built-in dictionary, and map search give you features to play with, and cross-device syncing lets you save your reading position across devices.
Kdan Mobile's PDF Reader is an excellent free Android and iOS PDF reader that provides solid rendering and reading as well as a neat document scanning feature. PDF Reader supports bookmarks, outlines and thumbnails; it can also open password-protected files. Text search and a page slider allow you to navigate to where you need, while a text reflow option provides a comfortable reading experience on a small screen. Annotation tools let you easily mark up documents, and cloud support allows you to upload, download and backup documents. A scanning mode lets you use your camera as a scanner and create PDF files from your camera roll.
Markup - Annotation Expert is Kdan's beefier, professional-oriented version of its PDF viewer and annotation software for iOS devices. As the name suggests, the app includes markup and annotation tools for PDF documents and a Web highlighter through an in-app browser, as well as support for audio notes and digital signatures. The Cloud portion of the app supports a variety of storage and backup options, such as Dropbox, Google Drive, or Kdan Cloud. Limitations on the free version such as number of files stored are removed on the $9.99 Ultimate version, and a paid subscription to Kdan's Creativity 365 suite of tools includes more premium features.