One-SIM allows you to use your iPhone with any GSM network of your choice. You’ll effectively be tricking the iPhone into thinking that it’s still using the SIM card given by the carrier even though you would change the SIM. The method relies on an iOS vulnerability, which Apple could patch in the future. It works with all iPhones including the iPhone SE, 7, 7 Plus. 8, 8 Plus, iPhone XS, iPhone XS Max, iPhone XR, iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max, iPhone 12, iPhone 12 Mini, iPhone 12 Pro, iPhone 12 Pro Max, and supports as iOS 14 +

Unlock your iPhone with one sim for any carrier like and many other: 

AT&T, T-Mobile, Sprint, xFinity, Verizon, U.S. Cellular