If multiple people in a group have access to a shared account (for example, the email address of a group) it's important that everyone that needs access sets up multi-factor authentication. If many people have access to a same accounts it means that the password to that account is shared, and when a password is shared there is a higher chance that it gets in the wrong hands.
It's also really important that not only one person has multi-factor authentication for a shared account. Doing this locks other people from the access they need, and you risk completely losing access to the account, because if that one person leaves the group or is not reachable for some reason, no one in the group can access the account any more.
There are multiple ways for multiple people to enable multi-factor authentication on a shared account: