Hello, you can read all the mandatory information in the links in hidden area, you probably have a translation program. Invoices are considered business letters, and the information is mandatory.
It's also a good idea to provide your bank account details, IBAN, and SWIFT, even for multiple banks. It should be clear which subject line to use for the transfer so that the accounting department can quickly assign everything.
Furthermore, every business letter must be formatted accordingly, there are guidelines for this.
And since the beginning of this year, you must also be able to send an e-invoice.
The relevant links are in the hidden area.
regards
Josef