The Scale Line Element Tool, located in the Print Map window, allows users to add a Scale Line onto their map before printing.
Before you can add a Scale Line to your page layout, you must first have a map in your layout selected so the Scale Line element will know how to set it's unit scale. Clicking on the Scale Line button will open a Scale Line window that allows you to set up the new scale.
Background - Sets an Area Style as the background of the Scale Line
Unit System - Sets what unit measurements will be displayed on the scale
Drag Mode - Toggles the scale to either be in a fixed position on the page layout, or draggable to be moved around