How can I add a Product subcategory?

You can add a Product subcategory by customizing the Product Type and Product Category fields using Custom Fields with picklist values.
Follow the below steps to add a Product subcategory:

1. Log in to your CRM account.
2. Go to Inventory.
3. Go to Catalog > Products. The List view of Products opens.
4. Click the Settings icon from the Products module.
5. Select Customize > Picklist Values. The Picklist Field Values page opens.
6. Select Subcategory from the drop down list of Select Picklist in Products.
7. Click Add Value.
8. Enter or select the following information:
   1. Item value: Enter the combined total of all included Product line items.
   2. Select custom color if required.
9. Click Save.