ArcGIS Pro 3.0 API Reference Guide
ArcGIS.Desktop.Editing Namespace / AnnotationProperties Class / FontSize Property

FontSize Property (AnnotationProperties)
Gets and sets the font size.
Syntax
public Nullable<double> FontSize {get; set;}
Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

ArcGIS Pro version: 2.2 or higher.
See Also