Inventory and stock

If you manage stock for your product, you can have WooCommerce track the quantities. Under Product data | Inventory, you can enter something for the following:

• Enter a value for SKU (Stock Keeping Unit), which is an ID for a product.
• Check Manage stock.
• Once Manage stock is checked, you can enter the Stock quantity.

I'm a big fan of setting the Low stock threshold, which will email you when your product is low in stock so you have enough time to order or produce more products.