HI @DaedalusK71, I'll help sort this one.
In QuickBooks Desktop, you can create a billable expense for services from customers linked to a certain cost or subscription. Let's create first the item which will determine your profit. I'll show you how.
- Go to Lists.
- Select Item List.
- On the Item menu, select New.
- Under TYPE, select Service.
- Enter the name of your new item.
- Put a checkmark on the This service is used in assemblies or is performed by a subcontractor or partner selection.
- Type in the amount of subscription in the Cost field.
- On the Sales Price field, enter the amount you will accept from your customers.
- Select the expense and income account accordingly.
- Click Save & Close.
Once done, use the recently created item to enter expense to pay the subscription from the payment made by your customers. You can do so by following the steps below:
- Go to Banking.
- Select Write Checks.
- Under Items, select the recently created item.
- Below the CUSTOMER:JOB column, select the name of the customer.
- Put a checkmark on the Billable tick box.
- Click Save & Close.
From here, go ahead and create the invoice and use the screenshot below as your reference:

I'm adding this article with the topics you can use while recording the common customer transactions: The Customer Transaction Workflows in QuickBooks Desktop.
It'll always be my pleasure to help if you've got additional questions about QuickBooks payments. Use the Reply option below and surely I'll be here ready to assist you. Take care and stay safe!