This article provides steps for updating and resetting your MFA (multifactor authentication).
Microsoft 365 Login
From the top right of the page, click your Profile icon and choose View account.
(a) Add a sign-in method: Click +Add sigin-in method to add a new MFA sign-in method.
(b) Change or delete a sign-in method: Click Change or Delete to modify or remove an existing MFA sign-in method.
(c) Lost, Replaced and Stolen Devices: Use the Sign out everywhere to disable use of MFA on devices you no longer have access to.