Quick Add a New Item While Creating a Document
The Quick Add option is available from all documents except sales receipts and receiving vouchers. See Add a New Item While Creating a Document for instructions to add an item while making a receipt or voucher.
With Quick Add, you enter only the basic item information needed to complete your current document quickly. Later, you should go to inventory and edit the item record, adding other information as needed. If speed in entering the new item is not required, we recommend you use the full add Item procedure instead, where all item information fields are available to complete at one time.
To Quick Add a new item from a document:
Scan the item bar code in the Enter Items field on the document.
OR
Type the item name or a search string in the field and press Enter on your keyboard.
Technical Note: Enter a search string that you know isn't an item identifier for any existing item in your inventory. Do not click Find Items to the right of the Enter Items field; this will open the item search window.
In the No matching items found message, select Add as New Item.
In the Quick Add Item window, enter as much information as you can.
Department Name and Item Name are required.
It is recommended that you enter the price, average unit cost (if known), and tax code so that this information is properly applied on the document as necessary.
If the item has a UPC bar code, you can scan it into the UPC field.
Choose Save and Select. You are returned to your document with the new item listed.
Don't forget to return to inventory later and edit the item record to add other important information.
QuickBooks financial software Note: Adding an item and immediately selling it 
Notes:
You can tell Point of Sale to always take the same action when the No matching items found message is displayed. Select the Remember my choice... check box and then choose an action. If necessary, the message can be reset using the Bring back all one time messages option in company preferences.
If necessary, you can choose Switch to full New Item screen from the Quick Add Item window to finish adding the item to inventory with all item fields available.