The most straightforward way to change your Android phone number is to change it directly through your phone carrier. You have to interact with them – either by calling customer service, using a website, or visiting an authorized store – to get the ball rolling.
Not all carrier numbers change the same way, so you should dig into the fine print before migrating. For example, changing your number with AT&T is free if it’s within 30 days of activation but will come with a $36 fee if it’s been active longer. Verizon, on the other hand, won’t charge you for the number change if you use the My Verizon app or through the website, but will charge you $15 if you use the customer service. Sprint won’t charge you for changing numbers, but you can’t change three times in 30 days. And T-Mobile offers one free number change per year if you use its ScamShield service, but it will charge $15 without it.
Whether you choose your new number also depends on the carrier. Some won’t let you, some will let you pick the first three numbers but not the last four, and so on. The same goes for waiting times between changes. Depending on the service it may take a few hours to activate, or immediately (after resetting your phone).