On your Mac, choose Apple menu > System Settings, click Privacy & Security in the sidebar, then go to FileVault. (You may need to scroll down.)
Click Turn On next to FileVault.
You might be asked to enter your password.
Choose how to unlock your disk and reset your login password if you forget it:
iCloud account: Click “Allow my iCloud account to unlock my disk” if you already use iCloud. Click “Set up my iCloud account to reset my password” if you don’t already use iCloud.
Recovery key: Click “Create a recovery key and do not use my iCloud account.” Write down the recovery key and keep it in a safe place.
Click Continue.
If your Mac has additional users, their information is also encrypted. Users unlock the encrypted disk with their login password.
If there’s an Enable Users button, you must enter a user’s login password before they can unlock the encrypted disk. Click Enable Users, select a user, enter the login password, click OK, then click Continue.
Updated over a year ago