All stores are not the same. But generally, the open screen of a POS system includes:
Options section: Where you can find all the menus for the POS system's functions.
Discount section - In case it is a special-offer product that was not in the system (usually requires managers to authorize).
Gift Cards section - If the customer is purchasing with gift/discount cards.
Enter ID - Some systems might include this option for costly sales or people purchasing alcoholic beverages.
Check out this video presenting the menu of a POS system at Walmart. It takes less than 2 min.
Disclaimer: Names might vary from system to system.
Photo by pch.vector on Freepik
Reference: How to Use a POS Machine, Step by Step Explained by Team NationalViews