Inventory items are the physical items that you sell in your store.
For example, let's say you sell Bubba Kush .5g cartridges from Happy Farms. Each cartridge is an inventory item in Greenbits.
When you receive a Package/Lot/SKU of a Product, you are adding inventory items to your Greenbits inventory, so you can sell them in your store.
When you sell an inventory item from the Register, Greenbits deducts the quantity sold from the Package/Lot/SKU connected to the inventory item. If your state tracks cannabis, Greenbits reports that sale to your traceability system.