For online orders, it's possible to change the buyer's details on the tax invoice. For example, if they forgot to put in their business name and ABN, this can be added even after the transaction is complete.
You can only change the invoice details for ONLINE orders. For those paid by invoice offline, you will need to generate a new invoice instead.
How to change the buyer details on online order tax invoice/receipt:
Go to Reports > Orders via the top menu bar
Search for the order by Order ID, buyer name or email
On the right-hand side of the order interface, click Actions > Edit
Update the purchaser details and double-check everything is correct
Scroll down and click Update
Click the Actions button again and resend tickets to resend their order confirmation email or download invoice if you wish send this manually