whenever I'm typing an email or a note/letter, etc. my cursor will suddenly jump to somewhere else in the document. typically somewhere above where I'm typing. What am I doing wrong, because apple says they fixed it when I sent it back.
We understand the cursor isn't working properly on your Mac. We're happy to offer some guidance.
You can first try starting the computer in safe mode to see if the issue still occurs.
How to use safe mode on your Mac
It's also a good idea to check for any available updates on your system.
Update macOS on Mac
You can also set up a test user account to see if the issue occurs there, or if it's just isolated to your user account.
Set up users, guests, and groups on Mac
If the cursor is still not working properly, we'd recommend contacting Apple for assistance: Get Support
Hope this helps. Cheers!
Make sure your hand not touching the trackpad when you are typing.