Free email forwarding / aliasing is a common feature at most mail hosts, but Microsoft appears to have left the process undocumented for their 365 Exchange offering. Here's how:
Head to https://admin.exchange.microsoft.com/#/contacts (click Recipients → Contacts if the link lands on the Exchange admin center Home page)
Click "Add a mail user"
Fill out required fields (Display name, Alias, User ID, Domain, and Password) and enter the desired destination address in the optional "External email address" field
Click Next → Create
H/T: 4IT
/misc | Dec 17, 2022