The steps in the link above are how to get the client data files. In the days of floppy disks and paper returns, you had a file cabinet. In more modern times did you keep a pdf file copy of what was sent to the government? You can copy those pdf files to the memory stick and stick it some place safe. If you did not make those pdf files, then use the data files you restore to your new computer and print pdf form that.

I did pencil copies of the tax returns, made copies and sent one of those copies with signature in pen.