How to get rid of "subtotal" on an invoice

Hello, @rainDancer! Thank you for taking the time to post your concern in the Community. It's our pleasure to assist you in customizing the invoice and showing the percentage discount and amount due in QuickBooks Online (QBO).

Adding a discount to an invoice in QuickBooks Online (QBO) is quite simple. We'll want to turn on the Discount feature from the Account and Settings page. We would be delighted to guide you through the process:

1. Click the Gear icon.
2. Select Account and Settings.
   
3. From the left menu, select Sales.
4. In the Sales from content section, click the pencil icon to edit.
5. Put a checkmark in the Discount checkbox.
   
6. Click Save, then Done.

Then, apply the discount on the invoice. Before that, I suggest calculating the discount value or percentage for the two payment methods. Then, add it beside the Discount field.

1. Go to the Sales menu, then choose the Invoices tab.
2. Locate the invoice that has already been paid but still has an outstanding balance.
3. On the lower right of the invoice, click Discount Percent (value).
4. Enter the early payment discount amount, then Save and Close.
   

For your guide, I recommend checking out the instructions from this link: Add a discount to an invoice or sales receipt in QuickBooks Online.

In regards to the second question, there is an option to see the balance due and only show the invoice amount by editing your Custom Form Style. We can add the account summary to the invoice to show the total outstanding balance. You can follow these steps:

1. Go to the Gear icon and select Custom form styles.
2. Find the invoice you're using, click the Edit or New Style, and select New to create a new one.
3. From the Content tab, tap the body section or middle part of the preview. From the Account Summary section, check the Show on Invoice box.
4.  Click Done to save it.

I'm adding this screenshot as your visual reference.

You can also visit these links on how to customize sales forms and reports in QuickBooks Online to make them more presentable.

Furthermore, if you wish to establish payment terms in QBO that allow you to offer discounts to your customers based on your agreement, check out this article: How to Adjust Invoice Payment Terms in QuickBooks Online.

If you require further help with adding your discount or managing your invoices, please feel free to leave a comment below. I'm here to assist you. Have a wonderful day!