Your SIM card will be linked to your account and any data you use will be added to your bill. You can’t buy a data-only SIM instead of a voice and data SIM. It’s an add-on, not a replacement.

If you don't have a SIM card or don't want to use one, you can still use a Windows or Mac computer with iTunes to set up your iPhone. Again, if you got a new phone and you're just having iPhone X ...