Conditional Formatting and warning notifcations

Hi and thank you to anyone that might help me.

And I apologize if this topic has been discussed already (maybe someone can send me a link to it)

I was wondering if I could have an excel form not be able to close and have a warning notification show if the user has not filled in the form correctly. In other words, I have several fields conditionally fomatted and if they don't fill in all the fields before trying to close the form it lets them know.

Is this possible?

Namaste