Passkeys are a more convenient and safer method of logging in to the Office 365 environment, it is encouraged that all users switch to this method for MFA.
How to set it up:
Step1: Go to My Sign-Ins | Security Info | Microsoft.com
Step2: Click add a sign-in method > Select, "Passkey in Microsoft Authenticator"
Step3: You will be prompted to open authenticator on your work phone and set up the passkey
Step4: Once finished you will see that it saved in the security Sign-In tab