Add your ways to get paid under Settings → Payment methods: bank transfer (IBAN, BIC), PayPal.me or any payment link. Pick one per invoice; the default comes from Invoice settings.
The invoice prints the details in its payment note with a QR code for the total: a GiroCode (EPC) for euro bank transfers that banking apps read, a PayPal.me link with the amount, or your payment link. Switch Print QR code off on an invoice if you don’t want it.