Settings->Security->Face ID. Set to "on".

By design, 1Password always makes you re-authenticate every time you lose focus on the app. But Face ID (or Touch ID) makes reauthenticating a lot less painful.

Setting FaceId is the first step, but you can also decide how often you have to reenter your password for reauthentication, or just so you don’t forget it. Directly beneath the face-id option.

Not exactly - you can lose focus without a problem

Recently 1Password has change on IOS (and I assume Android) to ask every two weeks for the password even if you use FaceId/TouchId - it says so on the app. This is probably what the poster was complaining about - I agree it is a nuisance.

For macOs and Windows it asks for the password every time the screen saver or sleep happens.

FYI there's a setting that lets you turn off the two week prompt or update it to 30 days.

Actually on iPhone it allows turn off for all time.