You can easily add a WhatsApp phone number in the Basic Settings section of the app. This is the number that will receive all chats initiated by your store visitors.
Please note that the phone number should be entered in the following format - Country code and phone number, without the + symbol.

For example, if your country code is +34, and your WhatsApp enabled phone number is 6043188675, the phone number that you should enter is 346043188675. As you can see, the + symbol is excluded.
After making any changes, don’t forget to tap the SAVE button to save your settings.
Make sure you enter a valid WhatsApp number by opening your store and clicking on the chat button to verify that the number is working as intended.