The angle is normally changed using the mouse, clicking the green rotation anchor, and moving the mouse around the center point of the object to change its angle.

Note:
The rotation has a snap effect every 45 degrees to simplify the most common rotation angles (0°, 45°, 90°, 135°, etc.).
To disable the snap effect, hold the ALT key while rotating the element with the mouse.

The rotation value can also be manually entered through the appropriate text box found in the Advanced tab.

Note:
changing the rotation angle using this text box will cause the element to rotate by keeping the Left and Top coordinates fixed, as opposed to rotating around the center point of the element, as happens using the mouse.

Or by using the Rotation menu items found in the Edit group of the ribbon..

In this last case, if you select the Rotate freely... menu item, a specific form will be displayed which will enable you to define a specific rotation for all selected items:

• Rotation angle: manually enter a value between 0° and 359.9° or drag the slider to define a rotation angle.
• Add to current rotation: select this option to add the value defined in the step above to the current rotation angle that each selected element is currently displaying.
• Absolute rotation: select this option to enforce the above rotation angle to each selected element, regardless of their current rotation.