1. Verify that your friend has installed WhatsApp to their mobile device.

2. Add your friend’s phone number to the Contacts list in your iPhone.

All international phone numbers must begin with the “+” sign, followed by the country code. 

3. Open the WhatsApp Messenger application. 

4. Tap on “Favorites.” 

5. Scroll to the top of your Favorites list and “pull down” using your touch screen. This action will refresh and re-alphabetize your Favorites list, and will also display any new contacts you have recently added to your phone book.