(Credit: GaudiLab, Shutterstock / GaudiLab)

Adobe Acrobat Reader (download for iOS) may be the go-to app for viewing, annotating, collaborating on, filling out, signing and storing PDF documents.

But you'll have to pay $24.99 per month for an Adobe Acrobat Pro DC subscription to take advantage of many of the app's most coveted features, such as organizing and editing PDFs, creating PDFs from documents and images, exporting PDFs to other file formats, combining multiple files into a single PDF and sending documents to reviewers. Or maybe you don't even need the comprehensive toolset that Adobe's premium subscription offers.

Whether you're looking for a more affordable PDF editor or only need one that's more barebones to complete a simple task like signing a contract, we've got you covered with our picks for the best alternatives to Adobe Acrobat Reader.

SEE: The best alternatives to Adobe Acrobat for making and editing PDFs in Windows in 2019

1. PDF Expert by Readdle

For free, PDF Expert 6 (download for iOS) lets you review, highlight, fill out, sign and password-protect PDFs on your iOS device. For a one-time payment of $9.99, the app allows you to make edits, such as changing PDF text and images and erase any sensitive data, using its amazing array of editing tools.


2. Goodnotes 4

Goodnotes 4 (download for iOS) is part note-taker, part PDF annotator -- all for $7.99.

Take auto-sized-to-fit handwritten notes that are easy to read and easily searchable later or smoothly draw perfect shapes with the app's high-res digital ink, confident that they'll be synced on all your iOS devices. Then comment to your heart's content on PDFs or fill out and sign forms in the app.


3. GoodReader

As its name implies, GoodReader (download for iOS) is an excellent PDF reader app that lets you quickly read, mark up, edit and, in three taps, sign PDF documents -- big and small for $4.99. The text-to-speech feature that reads files out loud to you is a great bonus.


4. iAnnotate 4

iAnnotate 4 (download for iOS) lets you peruse, mark up, sign and share PDFs and additional file types. As its name might suggest, iAnnotate specializes in annotation, allowing users to mark up documents in a variety of ways, with a pen, highlighter, note, photo, voice recording and a variety of drawing shapes. Then it allows you to compress them, so they can't be changed when shared and read by external PDF readers. You can also capture and convert web pages to PDFs for easy annotation and create brand new PDFs from scratch in the app.


5. PDFelement

The free Wondershare PDFelement (download for iOS) app helps you read, fill out, edit, mark up, convert, create and sign PDF files on your iOS device. You can even snap a photo of a document and convert it into a PDF to share with others.


6. Xodo PDF Pro

Xodo PDF Pro (download for iOS) allows you to quickly read, annotate, comment on, fill out, sign and manage your PDFs -- all for free.


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Joshua is an editor for CNET's Download.com. He covers the mobile tech and apps that power our lives and interviews celebrities about their favorite apps. Previously, he worked as an editor at Healthline and Gay.com and as a contributing writer for Mac Directory, MacAddict, SF Weekly, SF Examiner, and SF Chronicle.