Why are some general text symbol properties unavailable for labels?

The Angle and Vertical Alignment text symbol properties are not used by ArcMap's standard label placement engine and are unavailable. These options are only available when editing the properties of a graphic text element.

However, the Maplex Label Engine provides a set of label placement properties for advanced labeling. This includes rotating labels at a specified angle, and offsetting labels vertically from the labelled features.

To rotate labels by an angle taken from an attribute field, refer to Setting label rotation using a numeric field. To offset labels, refer to Offsetting labels from polygon boundaries and Offsetting line labels from a line.

The links in the Related Information section offer additional information on setting label positions, rotation, and orientation.