Answer:
select the object, click the Format tab, and choose a shape from the Shape gallery
or
Right-click the object, choose Change Shape from the menu, and then select a shape
Explanation:
Its definitely format tab or select the shape and right click. As you right click on the shape, the change shape option will be shown in the menu, and you need to select the right shape and click on it to add.
Or else, you can go to format tab, and click on it. Finally you can choose the shape from the shape gallery.
However, through design tab you can only change color or the position, alignment etc, or add new shape. However, you cannot change the shape.
And new shape option is never shown on right click. Hence, the above answer.
