Reading PDF's can be done in most browsers for free. However, editing them can require expensive software such as Adobe Acrobat
Here are some free alternatives for you to use :
OCRing
How to get a text from photos or flat PDF's. Easily convert a PDF to Doc File
Use Optical Character Recognition software online. Service supports 46 languages including Chinese, Japanese and Korean . OnlineOCR.net is a free OCR service in a "Guest mode" (without registration) that allows you to convert 15 files per hour (and 15 pages into multipage files). Registration will give you ability to convert multipage PDF documents and other features.
Edit PDF's in Browser or Program
PDF Escape allows you to edit PDF's in browser or you can download their program