Optical Character Recognition (OCR)

"Optical character recognition, usually abbreviated to OCR, is the mechanical or electronic translation of images of handwritten, typewritten or printed text (usually captured by a scanner) into machine-editable text."

You might need to make use of OCR software if you only have a paper copy of some notes that you then wish to incorporate into an electronic document as editable text.  In such a situation you could try scanning in your document and then using one of the following to convert the scanned image(s) back into editable text: