The figure is obtained by stacking together two rectangular prisms.
The large one, on the left, has dimensions 7,3 and 3 cm.
The small one, on the right, has dimensions 1, 3 and 3.
The volume of a rectangular prism is given by the product of its dimensions, so the two volumes are

Since the two rectangular prisms don't intersect, the volume of the whole figure is simply the sum of the two volumes:
