Hello there, restoredapparel.

Yes, you can delete and create new Products and Services in QuickBooks Online (QBO). I'll guide you how.

1. Go to the Sales menu, then select Products and Services.
2. Locate the item that you want to delete.
3. Beside Edit, click the drop-down menu and choose the option Make inactive.

In setting up your new Product and Services, click the New button and choose which categories you want.

For more detailed instruction, you can watch these tutorials: 

• ADDING PRODUCTS AND SERVICES TO QUICKBOOKS.
• Set up products and services.

Since you also mentioned that you're new in this, I'll also include another tutorials so you'll learn more.

• Learn QuickBooks Online.
• Video tutorials for QuickBooks Online.

I’m just a few clicks away if you need further help.