Welcome to the Community, @Muhammad Idrees.
You can set up Cost of Goods Sold (COGS) when setting up an item in QuickBooks Desktop (QBDT). This is where you can choose a specific COGS account you want to assign to a specific item.
If you're referring to setting up different COGS for a single item, this option is currently unavailable in QBDT. You can only add one account per item.
When you sell a stock item, run the Transaction Journal Report for the invoice/sales receipt, and you see the Sales/Accounts Receivable transaction and you'll see the Stock/COGS transactions which credit the Stock Asset account and debits the COGS accounts.
To learn more about managing COGS in QBDT, check out this article: Understand stock assets and cost of goods sold tracking.
In addition, the version of your QuickBooks Desktop (QBDT) is already unsupported. You may consider upgrading to a newer version. Check out these articles for further guidance:
I want to make sure everything is taken care of for you, so let me know if you have any other questions or concerns in the comment below. I'm always here to answer them. Have a good weekend!