If you need to populate custom information on the invoices, you can configure those as custom fields under the Invoice custom fields section.
Go to the profile icon>settings>operations and financials>invoicing>invoice custom fields
Click on New field
A New team member field pane will appear on the screen, for you to add the necessary details
Give the field a relevant name, for example, Purchase order number or Payment Method: Bank transfer, credit card, PayPal, etc.
Select the relevant Field type. For Purchase order the field type can be a number and for Payment method, the field type can be Single choice
Add a description, that would act like a tooltip for the users to understand what information needs to go into the field
After adding the necessary details, click save
Note: Here you can choose each field that needs to be displayed on the invoice, by checking the “display on invoice” box. For example, Purchase order can be a field shown on invoice and prepaid invoice can be a field not shown on invoice