When you turn on Quick Login on Web or Extension, your password is replaced with a 6-digit passcode.
This is the same passcode used across every device where Quick Login is enabled, including mobile. If you ever need to restore this wallet on your phone, you'll unlock it with the same passcode you already use on Web or Extension, instead of managing a separate password.
Good to know:
Your passcode becomes your sign-in credential going forward, replacing your password entirely.
Passcode attempts are throttle protected to ensure safety of your funds.