Adobe Reader is the most used program to read and edit PDF. I have used it for a long time. This software provides everything which I need to work with PDFs in a business environment. I use this software to open my PDF files and for the conversion of detailed design into PDF files. Its unique editing feature helps me make my detailed design PDF files error free. In my office, the "STAMP" feature of Adobe Acrobat Reader is also used to define file type (e.g. DRAFT ONLY, FOR OFFICE USE ONLY) to our clients. You can insert digital signatures which greatly speeds up teamwork. Security options are also provided by Adobe Reader, so documents cannot be modified.