Set up your Mac to be secure
Here are some things you can do to make your Mac more secure.
Use secure passwords
Require users to log in
If others can get physical access to your Mac, you should set up separate users for each person using the Mac, and require each user to log in. This prevents an unauthorized person from using the Mac. It also separates user files, so users only have access to their own personal files and settings. Users cannot see or modify the files or settings of other users. See Set up users, guests, and groups.
Secure your Mac when it’s idle
You can set your Mac to log out the current user if the Mac has been inactive for a certain period of time. See Set your Mac to log out when not in use. You should also require a password to wake it from sleep or from the screen saver. See Require a password after waking your Mac. For convenience, you can set up a hot corner to click whenever you want to immediately lock your screen. See Use hot corners to start the screen saver.
Limit the number of administrative users
One or more people can have administrator privileges for a Mac. By default the administrator is the person who initially set up the Mac.
Administrators can create, manage, and delete other users; install and remove software; and change settings. For these reasons, an administrator should create a standard user account to use when administrator privileges are not needed. If the security of a standard user is compromised, the potential harm is far more limited than if the user has administrator privileges. If multiple people use your Mac, limit the number of users with administrator privileges. See Set up users, guests, and groups.
Encrypt the data on your Mac with FileVault
If you have private or confidential information on your Mac, you can use FileVault encryption to protect that information from being seen or copied. FileVault encodes the information stored on your Mac so it is locked and cannot be read unless the login password is entered. See How does FileVault encryption work?