Create an account on Ultramsg: https://ultramsg.com/
Once logged in into Ultramsg, add instance
Click in instance, and you will see QR code. Scan this QR code from the smartphone where whatsapp is installed and that will be used to send messages.
Please send Instance ID and Token to info@reservationdiary.eu together with ReDi plugin API, so we can finalize the installation.
You can let your clients decide where they want to tall do they allow or not to contact them via Whatsapp. Without custom field it is allowed. In order to ask clients permission, custom field “Allow whatsapp” have to be added. See more information about custom fields here: Custom fields