The Enable Conditional Logic option allows you create rules to dynamically display or hide the field based on values from another field. Remember, to use conditional logic, you will need to create a drop down, checkbox, single line text or multiple choice field.
After enabling conditional logic for a field, you will have the option to show or hide the field depending on whether all/any of the conditions you specify are met. You can specify additional conditions by clicking the plus icon to right of the conditions. Clicking the minus sign will remove the corresponding condition.