Adobe Acrobat is a software that allows users to view, create, edit, sign, protect, and convert PDF files. It has much more functionality than the free Abobe Acrobat Reader. Watch Adobe's tutorials for Acrobat here.
Adobe Scan is a free app for mobile devices. It converts images into PDFs and automatically recognizes text. With an Adobe login, you can also compress files, export files into other formats, and use password protection.