Which rule type defines the appearance and content of a specific portion of a form?

The section rule is specifically designed to define the appearance and content of a particular portion of a form in Pega. It allows developers to group related fields and controls together, creating a cohesive unit within the user interface. This grouping becomes important for both organization and usability, as it enables a clearer layout that enhances the user's interaction with the form.

Sections can be reused across different forms, making them a flexible choice for maintaining consistent design and functionality within an application. By utilizing section rules, developers can efficiently manage the layout without duplicating efforts, as changes made in a section will be reflected wherever that section is used.

Other rule types mentioned have different roles. Layout rules focus more broadly on arranging components without defining specific content within those components. Flow Action rules relate to the actions that take place after form submission, guiding the user through the workflow. Control rules govern the behavior of individual UI components but do not encapsulate a section's overall appearance and content like section rules do.