How to log in without authenticator access

Hello, I want to add a mail account through Microsoft Exchange on my iphone (not this account).

During installation, I have to verify my identity with the authenticator app. I never installed that though and to add my account in the app, I only can identify myself via the app. Same when I try to login on the homepage.

I still have access to the mail account on my old phone, I have the password etc. I just can‘t use the only method to login because I never registered for it.

Thanks in advance,

Laura