When a question is marked as “Read Only” the applicant can view the question, but will not be able to enter any data for this question. Message question types and questions that have been linked to another question in the application are examples of Read Only questions.
(These two question types will automatically default as read only therefore you will not need to select them as “read only” when creating them). When creating a new question this question will automatically default to No.
Note: you would not want to mark a read only question as “required”.