The submit to WhatsApp function was disappeared when the new Google form was created by the add-on function directing to "neartail".
I checked the old form, and the function is still there.
Please provide a solid solution for this.
Open your form in Google Forms > click on the Neartail - WhatsApp form addon > click More options > click Customize > Edit page will open in a new tab > In the Edit page, click on the gear icon next to the Submit button > Button settings page will be displayed > click On submit > select Submit response to WhatsApp > configure the WhatsApp number and click Save. Please note that you must enter the country code when configuring the WhatsApp number.