Hello sneaker-sneakss,
QuickBooks Online is designed to keep things simple for people with and without accounting backgrounds, but there is sometimes a bit of a learning curve, so don't worry. Asking for clarification is perfectly fine, and I'd be happy to go over the difference between Category details and Item details on an expense form.
Regardless of which version of QuickBooks Online you have, every expense form comes with a Category details section. This section is so you can organize your business's expenses into various expense accounts for things like office expenses, hydro, travel, rent, phone charges, or whatever else. It's up to you how you'd like to set these accounts up and track to make things easier for you with reporting or come tax time. A category in this instance is the expense account. You can learn more about account types and setting them up here: Learn about the chart of accounts in QuickBooks
The Item detail section appears for users with QuickBooks Online Plus who have inventory enabled. You can use this section to show that you are buying items from a supplier that you want to add to your inventory. The inventory item would need to be set up first in order to choose it here. This article can help with that: Set up and track your inventory in QuickBooks Online. During the item setup, you can show that you've either already got some items with the quantity on hand or simply leave it until you purchase the item from elsewhere. You can also add items to your inventory using the bills feature: Enter and pay bills
I hope that helps clear some of that up for you. Don't hesitate to ask me more questions about these different features in QuickBooks Online. As for how you should manage your books, if you're still feeling unsure, I recommend connecting with an accountant.
As a tech support agent, I can't offer accounting advice, however, I can show you how to work with someone who can. QuickBooks Online comes with a My Accountant tab which gives you two options: invite someone you're already working with as a user to your account or use the Find a pro to help button to research accountants near you who are familiar with QuickBooks. While QuickBooks Online is designed to simplify accounting data entry, getting accounting advice is still something we leave to the professionals. It never hurts to have someone like that on your side.
Wishing you the best with this.
