Password change

Apple will not change passwords for you. That is something you have to do on your own. Please check this link for instructions:

Change your Apple ID password - Apple Support

If you want to change the phone passcode, check this link.

Set a passcode on iPhone - Apple Support

If you are referring to changing your Apple ID password Apple support is not needed, you are in full control on your end. However, Apple Support phone call or chat can walk you through doing it step by step if you prefer.

Can you tell us more about your password issue and we can try to help, too?