Those two commands are wrong here so if they're written that way in the Command form, both will fai but we're not giving up that easily. 😀
You may not be in the folder where the document is filed so the syntax might have to include that information to tell the system what to do.
If you arrived at the C:\Users\Documents folder and you can see the filenames oincluding the one named sales.docx, the syntax you're using should work. If you're outside the Documents or whatever folder the file shows up, you will need to include the name of that folder.
Just stop at the C:\ prompt and type
ren c:\users\documents\sales docx c:\users\documents\salesbackup.docx, assuming that is the complete path. Copy cannot include the renaming...