A per-point roll can be added through the editor, which is accessible here:

Once enabled, data points can be added. Represented by yellow circles, which can be rotated using a mouse drag

This is particularly useful for rollercoasters.

Procedural roll

Under the “Deforming” section, you can add a procedural rotation roll to the mesh, allowing it to twist around the curve.

This adds a constant rotation to the entire mesh.

Hint: Set the frequency to 0, and the mesh completely rotates around the Spline’s axis.