What is the contact message within the Personal Page configuration?

The contact message within the Personal Page configuration is the default message that will be sent to you by anyone who opens your WhatsApp link. It serves to help you identify that the message from that person comes from your personal page.

Anyone who enters your personal page and clicks on the WhatsApp symbol will be redirected to the WhatsApp page to send you a message.

And if they click send, it will automatically send you the message you configured from their phone.