How to convert a personal account into work or school account in microsoft authenticator app?

I need to join a company that requires me to sign in to their website using the Microsoft Authenticator app, where my Microsoft email account should be set as a work or school account. But my email is set as Personal account in the app. And I can't sign in to work or school account with it, as it says "you cant sign in here with a personal account. use work or school account instead." What shall I do? I need that email as work or school account only.