If your WhatsApp number is under PENDING status, it means that the meta official is reviewing your account at the moment.
Please kindly check meta official document for your reference. Thank you!
How to check number status in meta background:
1. Step 1: Enter https://business.facebook.com/
2. Step 2: Click WhatsApp account, choose the account, and click WhatsApp Manager.
3. Step 3: Then you'll be able to check the status.
