Hello there, mmpoolmd.

The option to modify the default fields isn't available. However, I have a workaround that you may want to consider.

We can select as to how we want their name to display as. I'll show you how:

1. From the Sales tab, select Customers.
2. Select your customer.
3. Go to the Customer Details tab.
4. Click Edit.
5. In the Display name as field, select where it displays their last name.
6. Select Save.

I've also added these screenshots as your visual guide:

You can also take a look at these articles when creating an invoice and paying it online:

• Create invoices
• Send online invoices

I'm just around if there's anything else that I can help you with. Stay safe!