Create a sharing-only user account on Mac
If you want to give someone limited access to your computer, you can create a sharing-only user account to enable the person to access only the files and folders you specify.
On your Mac, choose Apple menu > System Preferences, then click Users & Groups.
Click the lock icon at the bottom of the pane, enter an administrator name and password, then click Unlock.
Click the Add button at the bottom of the list on the left.
Click the New Account pop-up menu, then choose Sharing Only.
Enter a name and password for the user.
Click Create User.
You can also create a sharing-only account for one of your contacts when you set up file sharing.
You can also specify which users can share your screen.