How can I log in to my new Apple Account on iPhone 6s?
Allow me to login new Apple account
[Re-Titled by Moderator]
Original Title: Understanding Apple’s password safety notification on iPhone
Question marked as
Read the support articles:
Set up your iPhone --> Set up your iPhone or iPad - Apple Support
Set up iPhone --> Set up iPhone - Official Apple Support
You will need to sign out of your old account first.
The above may be simplistic but it would help if you provided more detail as to the exact issue.