Unlock your Mac with Apple Watch
When you’re wearing your Apple Watch, you can use your watch to unlock your Mac after waking it, instead of entering your password.
Note: To use Auto Unlock, your Mac (a mid-2013 or later model) must have macOS Sierra or later installed and your Apple Watch must have watchOS 3 or later installed. You must be signed in to iCloud using the same Apple ID on both devices, and two-factor authentication must be turned on for your Apple ID. Make sure your Apple Watch is unlocked.
Turn on Auto Unlock on your Mac: Choose Apple menu > System Preferences, click Security & Privacy, then select the “Allow your Apple Watch to unlock your Mac” checkbox.
If necessary, click the lock icon at the bottom of the pane, then type an administrator name and password.
Unlock your Mac: Wake your Mac from its idle state by pressing any keyboard key or, on a portable, by opening the display. The screen indicates your Mac is being unlocked.
System Information can confirm if your Mac supports Auto Unlock. Choose Apple menu > About This Mac, then click System Report. In the sidebar, click Network, click Wi-Fi, then look in the Interfaces section for Auto Unlock.
If you’re the administrator for another user on your Mac, you can log in to their user account and turn on Auto Unlock for them, as long as their Apple ID uses two-factor authentication and their Apple Watch has watchOS 3 installed.