Here is where you will learn to create a non-stockable, non-inventory item not necessarily associated with any particular Style or Substyle.
There are many reasons to create an item that won't have inventory. The most common would be if an item is a supply, service, or bundle. You can also add a general SKU for things like Shipping Fees in order to use them in Credit Memos (see the Unaffiliated Credit Memo section in this article about Credit Memos for more details).
Non-Stockable
Go to Inventory > Product Management. 
From the Inventory List screen, click Add. 
This will take you to the Inventory Management screen in Add Mode. Enter your SKU for this item.
Caution: There are certain characters that will not be accepted in a SKU:
? | % | , | & | = | ' | " | \ | leading space | multiple continuous spaces
Best practice is to only use letters and numbers in SKUs. However, there are some characters that you can use.
Characters that will be accepted:
- | _ | $ | # | @ | !
Choose the appropriate option from the Inventory Type dropdown list.
Note:
Product, Material, and SemiProduct types will typically be Stockable items.
Service, Supplies, Allowance, Virtual, Auxiliary, and Other types will typically be Non-Stockable.
Click Show More to add additional General information.
Under Product Detail, you can enter Pricing, Size & Color info (likely irrelevant for a non-stockable item), and Other Settings. Most importantly will be Product Control which is where you will toggle Non-Stockable to on.
Warning: The default setting will always be Non-Stockable = off.
Inventory is where you can view what you currently have in your inventory. We go over adding/adjusting inventory in the Inventory Adjustment articles: Inventory Adjustment WMS, Inventory Adjustment ERP. Because this is a non-stockable item, however, Inventory will not be relevant here.
Custom Attributes is where you can assign pre-set Attributes that were created during onboarding.
When you're done, click Save.
Click Yes.
Component Item
This user guide also applies to items that can be stocked but do not correspond to a particular Style, such as fabric or buttons (or anything else that might be a component piece of an item). This would be considered an Inventory Type: Material.
See related: