How do I apply a 10% discount on an invoice?

Hi cburakpld, 

QuickBooks Online offers the flexibility you need in order to enter discounts on invoices. I'll be glad to point you in the right direction so you're able to do this without running into issues. 

You can enter a discount easily into QuickBooks but you have to turn on the feature through your settings. Here's how: 

1. Click on Settings ⚙ and then Account and Settings.
2. Click on the Sales tab on the menu.
3. In the Sales form content section, select the pencil ✏ icon to edit it.
4. Select the Discount checkbox to turn it on.
5. Then hit Save and then Done.

This adds a discount field to your invoices. I encourage you to check out the following article that shows you how to: Add a discount to an invoice. 

Let me know if this info helps. I'll be one message away in case you have other questions. Otherwise, I wish you a great rest of the day,