Generally, the 4 types of inventory are as follows:
Raw Materials:
If you are a manufacturer, then you need raw materials to complete your products. The materials need their separate inventory, as they are usually bits, pieces, and component pieces that need to be stored away with extra care. Raw materials inventory consists of two types of raw materials i.e. direct materials which are used directly to finish the production of goods and indirect materials which are part of the equipment needed to complete the production of goods.
Work-in-Process:
This inventory consists of raw materials that are in-production, waiting to be processed as the finished products. So, whatever materials are needed to complete the production of your goods are found in this inventory.
For example, if you are baking a cake, batter is the kind of thing that would be found in the particular kind of inventory.
Finished Goods:
As the name suggests, this is the inventory that contains all your finished products. This is usually the kind of inventory most retailers that are not manufacturing their own products need to pay attention to. Essentially, the stock that is listed on your website will be found in this type of inventory.
It is the most straightforward of inventory types and most businesses would know how to manage this one.
Overhaul / MRO:
This type of inventory is also known as Maintenance, Repair, and Operating supplies. Again, as the name suggests, this inventory consists of the bits and bobs that are required to ensure the functioning of your operations.
So, things like paper, highlighters, and pens would be considered as a part of your MRO inventory as they are not needed for the actual production or selling of goods, but are still necessary to maintain your overall operations.
And remember, with the right inventory management system eCommerce businesses can optimise all of these types of inventory.