If you use Google Authenticator and still have access to it in your old phone, you have the option to transfer your account. To do that, (1) click on three dots on the top right corner, (2) select "Transfer account", then (3) "Export account". If you are using a protection pin on your phone, you'll be required to insert it. Once you are done, you will be shown a list of all your accounts. Click on (4) Continue and scan the code with your new phone.