WhatsApp quickly and easily recognizes which of your contacts are using WhatsApp by accessing your phone's address book.
Adding a new contact
- Save a contact's name and phone number in your phone's address book.
- If it's a local number: Save the number in the same format you would use if you were to call that contact.
- If it's a foreign number: Save the number in full international format:
- + [Country Code] [Full Phone Number].
- Omit any leading 0's from the phone number.
- Open WhatsApp and go to the Chats tab.
- Tap the new chat icon > More options > Refresh.
If you can't see your contacts:
- Make sure you have allowed WhatsApp to access your phone's contacts in your phone's Settings app.
- In your phone's address book, make sure that all accounts and groups are set to "visible" or "viewable".
Learn how to add a contact on: iPhone | Windows Phone