Your new password must be at least 12 characters long, contain an uppercase letter, a lowercase letter, a number and a special character.
It can't contain any part of your name or be something that's too easy to guess ("marymount" for example).
You can learn a little more about good password security here:
[https://saferinternet.org.uk/blog/password-security-understanding-the-basics](https://saferinternet.org.uk/blog/password-security-understanding-the-basics)