Settings › users. Require 2FA is per person, not a switch for the whole company. They enrol on the next sign-in. This page does not show a QR.
The MFA column is off until they have enrolled. Require 2FA is on the row. It applies to that person only. Invite a teammate is how the row got here. Your account, timezone and sessions is where each person sets up their own authenticator after you require it.
The label turns into confirm: require 2FA. Press it again to save. Until you do, nothing has changed: the next sign-in is still a password. After you confirm, a password sign-in opens only the enrol screen until they scan a code from their own authenticator app. Google or Microsoft sign-in still asks for that code. This shot stops before the second press.
The button is two-step. The first press arms it. The second press requires 2FA. This shot stops on the first press. Their own authenticator is set up under Settings, on their machine, and that QR is not published.