Your actual tax data is in a file, like a word processor or spreadsheet file. It is usually located in the documents folder and will have a name like "yourname 2025.tax2025". You can delete this file, but you should keep a copy, and you should also generate a PDF and save that for later, before you delete the main file.
If you also want to remove the program from the computer (uninstall) you may need your friend to log in with their administrator password.
