post https://app.pennylane.com/api/external/v1/customer_invoices
This endpoint allows you to create a invoice based on a specific payload. Pennylane will generate a pdf for you.
How the create and update flags are working together:
- create_customer: true, update_customer: true => create the customer or update the customer
- create_customer: true, update_customer: false => create the customer or raise an error
The api will check that all the customer attributes given are the same in this case - create_customer: false, update_customer: false => find the existing customer or raise an error
- create_customer: false, update_customer: true => find the existing customer and update it