Compression is process or methodology which is used for data compression and logical size of a file is reduced to save disk space for easier and faster transmission over a network or the Internet and working on the Compression algorithm that reduce the file size according to the original file size. in the Compression file compression is achieved by the data Compression software that creates a compressed version of each processed file and that file compression works by scanning an entire file, identifying similar or repetitive data and patterns and replacing duplicates with a unique identifier. This identifier is usually much smaller in size than the original word and consumes less space. Thus, the size of the Compression file is considerably smaller.