PDF Extra

Digitize, edit, combine, convert, compress, and sign PDFs with one user-friendly tool

This is a great app!

PDF Extra is a great app for iOS that lets you merge, split, annotate, and sign PDF documents. It's really easy to use and has a great user interface. The pro version gives you more features, like the ability to convert PDFs to other formats and to password-protect your PDFs. Overall, PDF Extra is a great app that I would highly recommend to anyone who needs to work with PDFs on their iPhone or iPad.