Unknown icloud email in auto fill

Hello all, my wifes phone suddenly has an email address that should up in her auto fill we have no idea where it came from. She has never let anyone else use her phone but us, the icloud email address is not in her contact card, its not in any of her contacts, it is not in her passwords, and also it is not in the safari settings. We also have 2 factor authentication on her account and have seen no unknown activity.

So how could this get on her phone, how do we remove it, and has she been hacked in some way we don't know about?

[Email Edited by Moderator]