Thanks for sharing your concern here in the Community. I've got the steps to categorize your purchased items.
You can create categories for the purchased items in QuickBooks to organize and track them easily. You can refer to the steps below for guidance:
Go to the Gear icon, then select Products and Services.
Click the More dropdown, then select Manage categories.
Select Create New Category.
Enter the category name in the box, then click Save.
Once done, you can record the inventory item and add this new category to these items. Here's how:
In the Products & Services tab, click the New dropdown.
Select Inventory item.
Enter the necessary fields.
In the Category field, select the category you created.
Click Create New to save the item.
If you're using Simple Start, you can use other item types, like non-inventory items, to record this. Also, you can upgrade your subscription to Plus or Advanced to get this feature.
Moreover, if you want to track your inventory, you can turn on the inventory tracking. You can follow this guide for reference:
Click on the Gear icon, then select Account and Settings.
Select the Sales tab.
Under the Product and Services section, click on the Pencil icon to edit it.
Turn on both the Track quantity and price/rate and Track inventory quantity on hand.
Turn on the Show Product/Service column on sales forms.
Click Save, then Done.
Additionally, you can create an invoice or a sales receipt after you set up your inventory to track them when they sell.
You're always welcome to comment back if you have other concerns with setting up your purchased items in QuickBooks. We'd be delighted to help you out. Have a great day ahead!