How do I get her name out of my phone?

I recently purchased a iPhone promax 12 I didn’t set it up the first day and my 16-year-old step daughter wanted to play some games saw the phone plug it in and to get to the games she had to set up the phones basic stuff and in doing so she put her name and created an iCloud account because she does these accounts that are for nothing she just thought she could delete this out of there and it would be no big deal I’m not able to get into the number of things and I was wondering how to remove her name been able to one by one remove change the password How do I get her name Out of my phone I’ve tried everything and remove her iCloud accountAlso can somebody tell me how to import my Google photos to my photos iCloud