I often get calls for roadside service, the roadside service pays a portion of bill, and their customer pays a portion. How do you split the payment on a single invoice?

Good day, greybeardrvservi. 

I'll give you some insights on how you match split payments to a single invoice in QuickBooks Online.

It isn't possible to record split payments to a single invoice directly. If you have two split payments for an invoice, you can only match them through Banking page.

Like this:

1. Go to the Banking menu.
2. Choose the account tile.
3. Click to expand first payment. For example, the payment from the Roadside service or from their customer.
4. Tap on Find match.
   
5. In the Match transaction window, select the invoice you created.
6. Hit Save once done.
7. Repeat the steps for the second payment.

After that, the invoice should appear in your invoice list as paid. For more details in managing your bank transaction, check out this article: Categorize and match online bank transactions in QuickBooks Online.

I've also included this resource for future reference: Reconcile an account in QuickBooks Online.

Let me know if you still have follow-up questions by leaving a comment below. I'll be around if you need me. Have a wonderful day!