Save a shape to the shapes library in Numbers on Mac
If you created or customized a closed-path shape, you can save it to the shapes library. When you save a custom shape, the shape’s path, flip, and rotation properties are saved; size, color, opacity, and other properties aren’t.
If you’re signed in to iCloud and have iCloud Drive turned on, your custom shapes are available in any Numbers spreadsheet on your devices (but not in Numbers for iCloud).
Click a custom shape to select it, then choose Format > Shapes and Lines > Save to My Shapes (from the Format menu at the top of your screen).
The shape is saved in the My Shapes category of the shapes library, which appears only when you have custom shapes. Shapes appear in the library in the order you create them; you can’t change this order.
Type a name for the shape in the field that appears below it, or click the name to change it.
To delete a custom shape, Control-click it in the shapes library, then choose Delete Shape.
Important: If you’re signed in to iCloud and have iCloud Drive turned on, deleting a custom shape deletes it from all your devices.