You'll be prompted to pick a new number, but your ported number will soon replace it, so it won’t matter what that number is.
At the top left, click Menu > Legacy Google Voice. Google Voice will look different, but you're in the right place.
At the top right, click Settings > Settings.
Click the "Phones" tab.
Next to your current number, click Change / Port.
Select I want to use my mobile number. Follow the on-screen instructions to set up your new number.
What Can't you port
A personal Google Voice account number to a Voice for Google Workspace account numbers, such as one managed by your work or school.
A Voice for Google Workspace account number to any other type of Google Account, including personal accounts and accounts using a different Google Workspace domain.
A second Google Voice number to a Google Account that already has a Google Voice number.
A Google Voice number to a Google Account that hasn't accepted the Google Terms of Service.
Your account information, including your settings, voicemail, call history, text messages, and linked numbers.
> Legacy Google Voice. Google Voice will look different, but you're in the right place.
> Settings.