NOTE: Shape elements are available with the new smart layout; if your website template is still using the old grid, you can either select a new website template or stay tuned until your current template is upgraded to the smart layout
Within the website editor, open the Add elements panel on the left and find the Shape element. Drag and drop it anywhere on your template:
Click on a shape to see more options:
Change the shape
Change the color: use your website's color palette, or set a custom shade
Duplicate the shape and use it multiple times
Delete it