Showing and hiding the fields dynamically is done using the rules. See Difference between Form rules and Field rules to know more about IntakeForms rules

Consider the following use case:

• We want to show the summary field when a priority field is high or highest
• By default the summary field is hidden and has the default value: Incident reported, but when the priority is higher than medium we want a user to set the description themselves

We set the form rule to set the summary with default value

We also, set the summary field to be hidden by default on form load

We add the field rule to priority rule like this:

We also add another rule to Hide the field, when priority is lower than "High"

This way, we will have the "summary" field to be dynamically shown/hidden based on the selection made in "priority" field