Can I delete cost of sale and delete every thing related to cost of sale from my system?

Hi there, magic. 

I appreciate you visiting the community. Your Cost of Sales in QuickBooks Online can be made inactive with my assistance.

We can't completely remove it, though, in case you decide to utilize the information anyhow. To prevent it from appearing on reports and transactions, we can deactivate it.

Let me guide you through the steps:

1. Click the Gear icon.
2. Select Products and Services.
3. Drop down arrow from the Edit.
4. Choose to Make inactive.
5. Press Yes to complete the action.

I've got a few articles for your consideration that go into greater detail about how each of these items operates and interact with one another.

• Set up and track your inventory in QuickBooks Online 
• Add inventory products in QuickBooks Online 

You can ping me here by adding a reply if you have more questions about the cost of sales. I’m always here to help. Have a great day!