Where can you go to review the location (IP address) when administrators log in to your Microsoft 365 tenant?
Sign-ins
Authentication methods
Access review
Azure AD Identity Protection
The sign-in logs will tell you where users have logged in from.
https://www.gitbit.org/course/ms-500/learn/Auditing-sign-ins-and-other-actions-in-Microsoft-365-sH_Ee1DW1
https://docs.microsoft.com/en-us/azure/active-directory/reports-monitoring/concept-sign-ins