When we talk about PDF, then we will think about Acrobat Reader which it is a great tool to view, print and collaborate on PDF files. The drawback of Acrobat Reader is that it just can view the PDF files, but it can’t use to modify the PDF files.

When I worked in office last time, there are some of PDF files need to be modified, but I was too lazy to search from Internet to find a tool to modify PDF files, so I have wasted my times to retype in Word document files. But now, I know there are 3 great tools which can modify PDF files easily and they are free.

1. PDF-XChange Viewer – is a smaller, faster and more feature rich than any other FREE PDF Reader/Viewer/Editor available.

2. doPDF – is a free PDF creator that does what the name suggests, creates PDF files.

3 PDFTK Builder Portable -  is the lightweight PDFTK Builder packaged as a portable app, so you can modify, split and watermark your pdfs wherever you go.