If you have a new phone number but you don’t want to let go of your old one, How-To Geek suggests a smart solution: port the old one to Google Voice and keep both.
Google charges a one-time fee of $20 to port over an old number and, of course, that number has to be active. In other words, you’ll want to port beforeyou actually change your number.
From there, type in the number you want to port, then verify that number. (to do this, Google will call you to confirm). From there, you’ll pay the $20, and once your payment is complete, you’re finished.
Google will also show you how to connect a new number to your Voice account when you’re ready to start forwarding. For the full list of instructions, head to How-To Geek’s full post below.