A possible scenario where user permissions can be of use is when a business is selling at both retail and wholesale prices. That's a typical evolution of a company as it grows - to expand into B2C apart from B2B (or vice versa) - and that can be supported in Megaventory as well.
In this scenario, if your customer is an individual or a company entity, a different price list should load when you create a sales order. On top of that, you may have different people to manage B2C and B2B sales.
So in Megaventory, you can create two different types of invoices - one for retail and one for wholesale. Following that, you can grant access to both of them to a user that handles wholesale purchases and sales. Alternatively, you can choose to limit a user so that they can do either and not both.
In the above image, the user has access to both types of invoices. In a different example where they have access to one of them only, the drop-down menu would show just one option.
To activate this option you need to go to the click on your Profile Icon and select Account Setup and click at the "Restrict access to certain Document Types based on different user logins" checkbox.
Note: Do not do this while users are logged in or are expected to log in soon! This will take away their access based on documents unless you provide it specifically. It is suggested that this is activation is considered maintenance and only performed out of work hours and with adequate time to test the permissions.
To grant different access levels to a user, click on your Profile Icon and select Company & Billing (Admin). From the menu on the left, click on Users and then click on Edit User Permissions, next to the user you want to edit their access rights.