stop customers from changing password

How can I stop customers from changing their password once they have signed up? I want them to contact customer support if they need to do this.

Amember control panel > configuration > advanced: Find option 'User can change the following fields' and change the highlighted fields there.

Thank you.

Are all fields required on sign up? If so how do I make some of them optional? If not, how do I make only certain ones required?

Which ones?

You can have amember generate the password for them, and also have the amember system not allow edits.

David