Show and hide fields based on rules 

Clear the clutter and get to the point by minimizing the form questions your users fill out with Form Display Rules. 

To create form display rules, select the page which has the form you'd like to modify and edit the Form Component. 

Next, click on "Form Rules" and choose "Display Rules" and Click "Add New Rule

We'd like to set up a rule that if a job isn't assigned to anyone, Notify User shouldn't be visible. 

So let's create our new display rule as follows:

If Assigned to field is not blank, show the Notify User field, otherwise, hide it 

Now when our users will add a new record the Notify User field will only be visible if this job is Assigned to a User.