Currently, you can only set up invoices to six languages in QuickBooks Online, @userh-hock.

The available languages are the following: 

• English, French
• Spanish, Italian
• Chinese (Traditional), Portuguese (Brazil)

You may check this article for your reference: Send invoices in different languages.

In the meantime, I encourage you to visit our QuickBooks blog. This includes the new updates and product enhancements for customer's better experience. 

Moreover, I've added these links to help you manage invoices in QBO: 

• Create an invoice.
• Record invoice payments manually.

You're always welcome to post here anytime if you need help with customer transactions in QBO. I'm happy to work with you. Have a wonderful day ahead.

@userh-hock 

You may need an additional app to do so.

hello, I have the same issue. I need to generate german invoices within Quickbooks. What additional app would allow me to do this? thanks

I can help you look for third-party apps that works with QuickBooks, @markush. 

You can check for any available third-party apps that work perfectly with QuickBooks Online (QBO). You can go to the following link and click the Country dropdown arrow to verify if your country is supported by the QuickBooks apps: https://quickbooks.intuit.com/app/apps/home/.

Here's more information on how to create invoices in QuickBooks Online and on how to record invoice payments in QuickBooks Online. 

I'm always here if you need more help in creating invoices for your customers. Let me know by leaving a Reply below. Take care and have a wonderful day!

@markush 

What kind of business do you run? An exporter company, a service one, or else?