How do I send a customer an invoice for 50 percent including tax?

You can make use of progress invoicing feature, djohndi06.

This will allow you to create multiple invoices from a single estimate. With this option, you can invoice your client for 50% including taxes. The first thing we need to do is to turn on this feature.

1. Go to the Gear icon and select Account and Settings.
2. From the Sales tab, select the Progress Invoicing section.
3. Select the Create multiple partial invoices from a single estimate checkbox, then click Save and Done.

Once done, create an estimate for the full amount and save it. When it's time to invoice your customer, let's open the estimate. Click on the Create invoice button at the upper-right corner. On the pop-up, select the second radio-button, then enter 50% on the first box and select Create invoice.

You can now print or send it to your customer. You can also attach the estimate summary when sending the invoice so your customers can see the remaining balance.

We also have a report called Estimates Progress Invoicing Summary by Customer. You can search and pull up this report on the Reports tab. Use this for your guide to see the list of all estimates and the linked invoices.

This method is so simple. Tag my name anytime if you need more help. Wishing you all the best!

@djohndi06 

As additional option, should you need more feature in your invoicing, explore this app to integrate with QBO. You may find something useful for your needs.

http://get.practiceignition.com/quickbooks

Hope it helps.

@djohndi06 

IF, if you are asking how to invoice for one half the item total plus the full amount of sales tax (many states require this) - you can NOT do that using progress invoicing.  ie

widget, qty 4, total price $568.00

sale tax @ 8.25%, $46.86

Total invoice, $614.86

Progress invoicing will invoice (if you select 50%) $307.43

What I think you want is

item sale at 50%, 284

sale tax, 46.86

total partial invoice $330.86

QB can not do this