I would like to make a field mandatory, but only when a certain selection is made within another field (a choice drop down). i.e. if the choice drop down states "X to Y", it prompts a person field to become mandatory.
Hope that makes sense and is a simple rule.
Which forms designer are you using? You can use a rule to accomplish this in either the Responsive or Classic designer.
Follow these steps in the Responsive designer:
Let me know if you would like me to provide this configuration for a Classic form.