set Username and password to user

I would like to have a function where a user enters their email and phone.
This is written to a populated data database with a username and password set for the user.

1. User comes to blog to join.
2. User enters name, email and phone. (Required fields.)
3. User is sent an email with username and password.
4. Email sent need to be from a template with the database items injected.
5. Username and password is unique to use and cannot be resent again to any new user.

Example:
Dear John,
Thank you for joining xyz company.
Your username is [username] Your password is [password]
You may log in at [urllogin]

Thank you,
xyz team.