Financing an unlocked iPhone 16 Pro Max for all carriers

If you finance through Apple Card Monthly Installments or the iPhone Upgrade Program, it will be unlocked, no matter the initial chosen carrier. The only caveat is that upon selection the phone number you choose must be valid to that carrier. That step is for verification. So if you use either Verizon, T-Mobile, AT&T, or Boost Mobile, you should do that. If you can’t fulfill that, best is to pay full and contact your credit card company to finance through them. And financing through a carrier will be locked to them.

You can BUY an iPhone at an Apple Store that will be unlocked. In the US Apple Store you can finance it over 24 months. Don't know about the other countries tho.

In the U.S., if you select any of the carrier financing options from Apple’s iPhone ordering pages, the words about the phone being unlocked go away. I would assume that all carrier financing options come with carrier lock.

No

You will likely have to pay Apple in full for the purchase, but most credit card companies will provide you with an option to finance a major purchase.