I sold my inventory of clothing as closed my business. The sale of inventory was about $3,000 less than its wholesale value. How do I claim this loss?

[Carl]

You don't - at least not directly. What you got for the sale is as you know, included in your business income. Then in the COGS section you report what you paid for the inventory you actually sold in 2018. Depending on to many factors to deal with here, you may have a business loss, or you may just have less taxable business income that you would have otherwise.
"wholesale value"
The "value" just flat out does not matter. In the COGS section you report what you actually paid for the clothing that you acutally sold.

[Anita01 · Accepted solution]

You don't actually claim the loss.  You claim the sales and then you claim the cost of the inventory as part of your Cost of Goods Sold.