Adobe Acrobat Reader allows you to view, comment, fill out, and sign PDFs on multiple platforms.
Free software to quickly and efficiently view, create, and edit PDF files.
Free software for Windows that offers a practical solution to create, view, and edit PDF files.
Create PDF files from virtually any application.

Utility to extract and merge pages from PDF files.
Free utility to convert PDF files, extract texts from PDF files, in addition to many other features.