When you click Angular on the Create > Text/Dim menu, you will be prompted to pick an arc or a line for angular dimensioning.
If you choose an arc, its angular dimension will be displayed as well as the Select Point menu. Position the dimension with the mouse or the Select Point menu commands.
If you pick a line, you will be prompted to pick the second line. The angular dimension between the two lines will then be displayed as well as the Select Point menu. Position the dimension with the mouse or the Select Point menu commands.