To add a customizable shape:
1) Click on the Add Graphics button to the right, and then click the "Add Editable Shape" selection in the drop-down menu.
2) Drag the shape you'd like to add on to the page
3) Click on your shape to choose color, frame etc or grab a corner or top /bottom/left/right side to re-size
Keywords: custom shape, rectangle, square, line, make my own shape, draw my own shape, draw a shape, draw a line, draw a rectangle, create a box, draw a box