Blocking a phone number on your device does not necessarily block the same number on WhatsApp. WhatsApp is a separate messaging app that requires a phone number to create an account. If you have blocked a phone number on your device, it will not automatically be blocked on WhatsApp.
To block a contact on WhatsApp, you will need to open the app and navigate to the chat with the contact you want to block. Then, tap on their name or profile picture at the top of the chat, select “Block” from the menu, and confirm your decision. Once you have blocked a contact on WhatsApp, you will not receive any messages or calls from them, and they will not be able to see your profile picture or status updates.