Can they be given reminders that certain parts have not been filled out yet?

Can they be given reminders that certain parts have not been filled out yet? Not making them required, but perhaps as they go through the document before they submit, maybe a red exclamation point comes up on the fields that are still empty. So if they see the fields that have a red exclamation, it's not required that they fill it out, it's just a reminder that it's empty.
Thank you!

We do not have such feature for exclamation marks. A field can be either required or not required. We can submit a feature request, if you want.

However, you can make a field required based on user's answers. So, you can communicate with your users as they fill the form out. In order to do this, you should use conditions. You can check and follow this walkthrough:

https://eu.jotform.com/help/367-How-to-Make-a-Field-Required-Based-on-User-s-Answer

Let us know if we can be of any further assistance.