The Accountable app is mainly aimed at natural person self-employed, who can file taxes with simplified accounting.
If you have a company in the form of a UG or GmbH, you need to maintain double-entry bookkeeping (not covered in the app at this time) and to rely on an accountant to file your yearly accounts.
You are welcome to use Accountable in order to create, customize, and edit your sales invoices.
Our support team is available to help you and answer your questions. Don't hesitate to contact us.