Field Logic for Custom Forms
Field Logic enables you to control when fields are displayed, hidden, required, or optional according to conditions based on other fields located on the same form.
An issue was found in one of the phone models a company has provided to new employees. The company would like to require users to submit the phone model to handle issues more effectively.
Setting up Field Logic
Make sure you have Dynamic Forms enabled under Labs.
Click View Logic on the relevant custom form.
Define the Conditions.
Define the Actions.