How do you add a discount to an invoice? Mine app does not give me the option to do so

Hi there, 

Welcome to the Community. I'll be happy to show you how to add a discount to an invoice using QuickBooks. 

To do this, I can recommend using a web-browser to navigate the settings. Here are the steps:

1. Click the Gear icon.
2. Select Account and Settings.
3. Click Sales tab.
4. Click the pencil icon under Sales form content.
5. Put a mark into the box next to Discount.
6. Click Save and Done.

If you're using an invoice template, you can edit the template by following the steps below:

1. Click the Gear icon.
2. Select Custom Form Styles.
3. Select the invoice template, and click Edit.
4. Click the Content tab, and then click the pencil icon at the bottom of the invoice.
5. Put a check mark into the box next to Discount.
6. Click Done.

Give this a try and let me know how you make out when adding the discount to the invoice. I'll be on standby.