Overview
The Required Fields drop down at the bottom of the Current Form Element list allows you to specify which fields are required to be filled out before the form is submittable. The form becomes submittable once valid data is entered. Required fields have a red asterisk to indicate that field is required to users filling out the record.
Visual Indicators
In the preview section of the form builder, there is a tag which shows you if the information you've entered into the preview satisfies the required fields of the form.
Red Invalid Tag: The form cannot be submitted in its current state.
Blue Valid Tag: The form is ready for submission once all required fields are completed.
Min Items
Selects and Data Selects with the Multi Select option on will reveal a Min Items option. This will prevent submission until the minimum number of items has been selected in the multi select.
Repeatable Form Elements and Tables can have both a minimum and maximum number of items allowable.
Conditionals
Required fields hidden by conditionals will not stop record submission unless they are visible.