Viewers will learn the step-by-step process of creating a customizable inventory item with modifiers. The video explains how to streamline the process by cloning and adapting an existing item, then adjusting relevant details such as the item name, price, and menu color. The tutorial then provides a detailed walkthrough of creating modifier groups, defining the number of choices a customer can make, adding specific modifiers like ‘Bread Type’, and applying these to the inventory item. Lastly, the video demonstrates how to organize and clean up the modifiers for efficiency and clarity from the register perspective.