Is it possible to hightlight questions?

I have forms that get filled out when setting up a client.  Do we have the ability to highlight questions that were missed or not filled out correctly, save it, and send it back to the potential client? 

I think you may want to take a look to our Quiz app, although it will not highlight the wrong questions you will be able to show your users if their answer is wrong. 

Please, take a look on this guide in order to get more details about it: Turn-Your-Form-into-a-Quiz-or-Exam-

Now, if you need some questions to be mandatory, you may set the field as required, that will avoid users to submit the form without filling out that field. 

Let us know if you have any question, we will be glad to help.