When you add a text box, shape, or picture to a document, it is placed on an invisible layer. Layers let you stack objects and move them forward or backward. For example, a transparent rectangle can appear either in front of or behind a picture of a hammer.
Try it
On the View menu, click Print Layout.
On the Home tab, under Arrange, click Reorder.
Note
If Reorder is not available, make sure that the document contains at least two objects.
Drag the layer forward or backward to place it where you want it, and then click OK.