The change number feature allows you to change the phone number associated with your WhatsApp account on the same or a new phone. Before changing your phone number:
Make sure your new phone number can receive SMS or phone calls and has an active cellular connection.
Make sure your old phone number is currently registered on WhatsApp. You can find your registered phone number by opening WhatsApp, then tapping More options > Settings > tap your profile photo.
Change phone number on the same phone
If you’re changing your phone number and using the same phone, first insert the new SIM card with the new phone number into your phone.
Tap More options > Settings > Account > Change number > NEXT.
Enter your old phone number in the first field and your new phone number in the second field, both in full international format.
If you turn on Notify contacts, you can choose if you want to notify All contacts, Contacts I have chats with, or Custom... If you select Custom..., you'll need to search for or select the contacts you want to notify, then tap the check mark .
Your group chats will be notified when you change your phone number regardless of whether you choose to notify your contacts.
You'll then be prompted to register your new phone number. Learn more in this article.
Change phone number on a new phone
If you want to transfer your chat history, you’ll need to create a Google Drive backup on your old phone. Learn how in this article. If you don’t create a backup using Google Drive, you’ll need to manually transfer your backup, which you can learn how to do in this article.
After changing your phone number on your old phone: