Generally we are using two file formats zip and pdf. Zip files can be opened using a freeware 7zip
. pdf files can be opened using Adobe reader version 7.0 or above (More than 20MB). If you don't have Adobe reader or you want a light pdf reader , I strongly recommend you to download a freeware Foxit pdf reader
(less than 2MB). You will be having problem if you open the pdf files using adobe acrobat reader below version 7.0 since we are using pdf version 1.6 from 10/2006 to reduce files size of pdf files.