Microsoft authenticator - add sites

That app is seemingly being retired:

… https://www.macrumors.com/2022/12/13/microsoft-authenticator-watchos-app-discontinued/

… (I love how a long-standing ASC URL bug mungs links.)

iPhone and iPad have a built-in authenticator:

… Automatically fill in verification codes on iPhone - Apple Support

As for Microsoft support questions:

… https://answers.microsoft.com/en-us/ (these are the forums for Microsoft apps)

… https://support.microsoft.com/en-us/account-billing/how-to-use-the-microsoft-authenticator-app-9783c865-0308-42fb-a519-8cf666fe0acc

… https://www.microsoft.com/en-us/microsoft-365/blog/2018/08/27/microsoft-authenticator-companion-app-for-apple-watch-now-in-public-preview/

… https://support.microsoft.com/en-us/account-billing/common-questions-about-the-microsoft-authenticator-app-12d283d1-bcef-4875-9ae5-ac360e2945dd

As for Bill Gates, his telephone number is publicly posted, not that he’s much involved anymore.

A better choice would be Satya Nadella, and his office number is likely posted, so you could go that way.