I'll be glad if you can direct me on how to add the popping notification to my facebook page?

Please help me. I am yet to own a website

I'm not sure if i understand you correctly but if you mean you want to receive notifications from the submissions of your form, here's a guide on how to Setting Up Email Notifications.

Here's also a guide on Adding a Form to Your Facebook Page.

Please let us know if you need further assistance.
Regards