If you're trying to create an Invoice, you should be using InvoiceAdd
.
The only time you should be using OpenBalance is if the customer has an outstanding balance that's not the result of an invoice that you'll have in QuickBooks. e.g. if you're migrating from another accounting platform, you might have an open balance for someone when moving from the other system.
Beyond that, you should never be creating customers with an OpenBalance.
Instead, create an actual invoice. Here are some examples: