computer repair

Hi,

"repair person can't access my personal information, like documents, photos music?"

You'll need to do a backup.

Before you return your Mac to us, be sure to enable FileVault and back up your data. You may need the backup if your Mac needs to be reformatted during the repair process. Apple isn’t responsible for lost data."

Above information from this support article > Mac Service Answer Center - Apple Support

If you take your computer to an Apple Store remember Apple has FAR more to lose than you possibly could have. They are a HUGE company so your data's security is one of their primary concerns. However if you are really concerned, the best method is to backup your system and then do an erase of your system and then re-install Mac OS before bringing it in. Frankly, IMHO that is a complete waste of time.

Aside from a backup, I'd think the easiest way is to create another (guest) user, use a very simple password, and limit the apps/accessibility of the guest user. That way you can turn it over to the repair place and tell them the password you created so they have limited access (and no access to your account).