Most documents need to be filed electronically as PDF (Portable Document Format) files. Most word processing programs (Microsoft Word, Word Perfect, etc.) allow you to save or print or export your document as a PDF file.
If the document you want to file is in paper form, you may wish to scan the document to produce a PDF file. You should adjust your scanner settings to black and white and 300 dpi. This way, you will have a smaller file size to work with.