You should use Set Business Required to change the requirement level for a field. As shown in the following figure, the options to change the requirement level are Not Business Required and Business Required:
Figure 4.6 – Setting a field as business required
The preceding screenshot shows how to set the password field to be mandatory. Making a field business required makes the field mandatory. This means that if the field does not have a value, the form cannot be saved.
When editing a field, you can set the field as Required, Recommended, or Optional. Not Business Required is the same as the Optional setting. There is no equivalent to Recommended in business rules.
If a field is changed to business required, you should also ensure that the field is not hidden using the Set Visibility action.