If your order has already been placed, your delivery address can not be changed. You will need to cancel the order through the app or website and then reorder. If your order cannot be cancelled via the app or website, contact Customer Service to see if the order can be canceled in the event the order has not yet been prepared.
If you need to change your address for a future order, when you are on the checkout screen you can tap on the address to edit all specifications including the phone number.
You can also add or delete an address via the website by clicking on your photo to go to your 'Account Settings'.