How can I change my phone number and password on my account

You can change/add the number on your Apple ID. Look in the Security section when signed in online. You may have to add the new number before you can remove the old number. After the change, allow up to 24 hours for the change to sync. Before trying to make the change, sign out of Messages/FaceTime on all devices/computers.

Apple ID - Manage

If you know the current password.

Apple ID Password Change.   -  

ASC YouTube for How to reset your Apple ID password

 What to do after you change your Apple ID or password - Apple Support  -   I suggest doing this before you change your Apple ID or password.      

If you forgot the Apple ID (iCloud) password, enter the Apple (iCloud) ID, and click Forgot Password. See if you can get a Rescue or Notification email option if necessary. Link to contact Apple Support at the end of the 2nd article.

Apple ID - Manage  -     

Apple ID – Forgot Password  *