Welcome to the Community, leslief-wataugah. 

You can record a partial payment in QuickBooks Online. This way, the 50% payment will be registered, and the 50% will be tagged as a remaining balance.

Here's how:

1. Open the Bill that needs to be paid. 

2. Click on Make payment at the top. 

3. Enter the 50% of the payment in the amount section. 

Once you're ready to pay the remaining 50%, just reopen the Bill by going to the Expense tab and make a payment again.

You can also look at this article for further details: Enter bills and record bill payments in QuickBooks Online 

Keep in touch with me if you still need more help with this. I'll be here. Keep safe!