You need an OCR program (Optical Character Recognition). There are several free ones if you do a search. There is usually a cut down version of one supplied with the scanner/All in One. Did you receive a driver disk with the Scanner. The popular ones are Abbyy Fine Reade (Epson) and ReadIris (HP).
Perhaps someone else here can recommend a free one as I have never needed to use one myself.
You usually scan the document then ask the program to convert the scanned image into a text document. Then you need to edit it as it usually has a few errors, then save it to Word or whatever is appropriate in your case.