how can I apply discount to only some itams and not the whole invoice ?

Hi, Edina. In QuickBooks Online, you can discount invoices by using a percentage or a flat dollar amount. For your workflow, you can apply a fixed-price discount by adding a line item with a negative rate. This only works for flat dollar amounts and not for percentage-based discounts.

Here’s how to create a discount item:

1. Go to All apps, select Sales & Get Paid, then select Products & services.
2. Click New product/service.
3. Select Non-stock item or Service.
4. Enter the name “Discount” in the Name field. If you want to create multiple discount items, give each discount a unique name so they're easy to tell apart.
5. In the Sales price/rate section, enter the discount as a negative amount. Keep in mind that this is an amount and not a percentage.
6. From the Income account dropdown menu, choose the Discounts given account that QuickBooks created when you turned on the discount setting.
7. Select an appropriate tax rate so that the discount is nontaxable.
8. Once done, select Save and close.
   

Here’s a sample screenshot of what your sales forms look like after you put on a discount.

Should you have any other concerns while working in QuickBooks, please post again here in the Community. We're always got your back.