Introduction As portable computers become more personal and are made smaller, they reach some physical limitations for having a keyboard.In pen computers, the pen is used to do the job of a mouse in addition to its specie c task of handwriting input.This paper will provide some information about on-line handwriting recognition, OCR and signature very cation.Another method of recognizing handwritten or even typewritten text is to scan the image of the written or typed document and to have the computer recognize the content of it. This, known as OCR (Optical Character Recognition), is a good method of extracting information from our archives which have been generated over hundreds, even thousands of years.Typing illiteracy might not be very common in many western countries like the United States; however, it poses a big problem in countries like Iran or Arabic countries in which almost only secretaries know how to type in their native alphabet.Another reason for the practicality of a system which would accept hand-input is that with todays Technology it is possible to have handwriting recognition in very small hand-held computers, however speech systems could not yet be made as small as to t in a standalone hand-held machine.Many countries have recently adopted automatic sorting techniques that will recognize the addresses on the mail pieces and sort them accordingly.