Hello @shayxn,
Welcome to the community!
Do you have a pre-paid or a postpaid account? If you have a pre-paid account you will need to contact customer service and they will be able to do it for you.
If you have a post-paid account you can follow the instructions here also you have to make sure you are the account holder and logged in as the account holder or you will not be able to see that option.
