Gather Important Information
Putting an iPhone 7 order will require more than a credit card number so you'll want to have all of your important information nailed down ahead of time.
So what information should you have on you when it's time to order your new phone? At the very least, you'll want to have your Apple ID and any carrier login information in your possession. You'll need to know user names and passwords.
If you're the primary account holder, this info shouldn't be too hard to track down. If you aren't the primary account holder, now would be a good time to give mom and/or dad a call.
You'll also want to have your Social Security Number (or the account holder's SSN), the account billing information, and your shipping information available.
You'll probably have to ship your device to the primary billing address so if that's not your current shipping address, you might want to address that now.
Not having the proper information will slow your order process and it could prevent you from getting the iPhone 7 model you want in the time frame that you want.