Can I easily pay someone who has a set rate for adding something to my product whilst providing the customer with on invoice?

It's a delight to see you here, Square.

If you're using QuickBooks Online Plus or Advanced, you have the ability to create a billable expense. This expense is incurred on behalf of a customer when you perform work for them.

To continue, make sure that billable expense tracking is activated.

1. Navigate to Settings ⚙, then choose Account and Settings.
2. Go to the Expenses tab.
3. From the Bills and Expenses section, click Edit ✎.
4. Turn on the following:

• Show Items table on expense and purchase forms
• Track expenses and items by customer.
• Make expenses and items billable.

     5.Bill payment terms.

     6.Select Save.

Then, enter the billable expense. For more details, you can utilize this reference: Enter billable expenses.

You can manually add service fees to invoices in QuickBooks Online as well. For further details, please utilize this reference: Manually add service fees to invoices in QuickBooks Online.

Moreover, I've compiled some resources that can help you manage your invoices and payments in QuickBooks.

• Record the invoice payment
• Deposit your customer’s payment.

Please keep me posted if you have any further questions about handling invoices in QBO. I'm here to assist as needed.