You can easily add several Shapes as well as lines to your pages. For Shapes you can then add borders, shadows and fill, and adjust the opacity of that fill.
Once you select the shape you want, you will be prompted to select where you want the shape to be on the page. You can add a Border on your shape, adjust the thickness and color of that border, add a color to Fill the shape and adjust the color and opacity of that fill. If you do have fill on the shape, you can also add a Shadow to it. Shadows don't apply to Shapes without Fills. If you wish, you can also move the shape backwards or forwards in relation to the other elements on the page.
See also: Adding Lines