What is required to ensure a field must be filled in by the user?

To ensure a field must be filled in by the user, the correct approach is to set the field as mandatory. When a field is marked as mandatory, it establishes a requirement for users to provide a value before they can save a record or proceed to the next step within a transaction or form. This validation helps maintain data integrity and completeness, making it crucial for fields that hold essential information in the system.

In contrast, other options do not specifically enforce user input as a requirement:

• A field group is a way to organize fields within a form but does not impose any requirements for users to fill them out.
• Enabling field editing on lists allows users to modify fields directly in a list view but does not indicate whether those fields must be filled or not.
• Using fields for pop-ups could improve user interaction but does not denote any level of required input from users.

Therefore, marking a field as mandatory is the definitive approach to ensure that users must provide input before continuing.