I always ask for a deposit and the customer has a week before their event to pay the remaining balance. Is there a way to set up a payment plan on the original invoice?

We're unable to set up a payment plan, Shefcservices.

You can send an invoice reminder instead. This will help you remind your customers about their transaction due date. 

First, let's turn on the feature. Here's how:

1. Click the Gear icon.
2. Select Account and Settings.
3. Go to the Sales tab.
4. Click the Pencil icon in the Reminders row.
5. Tick the Use greeting box, then you can personalize the message.
6. Tick the Email me a copy at email address box (optional).
7. Click Save, then Done. 

Then, you can send the reminder manually. Here's how:

1. Click Sales, then go to the Customers tab.
2. Select the customer, then look for the invoice.
3. Click the Receive payment drop-down arrow, then select Send reminder.
4. Click Send. 

Your customer will receive the reminder. Once they pay, record invoice payments in QuickBooks Online. 

If you have more questions, please drop a comment below. 

@shefcservices 

To answer your question directly

No, QBO will not do installment invoices