Hi @Arno Tillwick ,
A Microsoft 365 account is needed in order to access power apps, and Power Apps are licensed per user, so they would need licenses as well.
However, one workaround might be to use Power Pages or try the solution described here: https://powerusers.microsoft.com/t5/Building-Power-Apps/Using-PowerApps-without-Office365-User/td-p/1470311
PowerApps is not supported on Q&A, so for additional support and examples I would recommend reaching out to the PowerApps community. https://powerusers.microsoft.com/t5/Power-Apps-Community/ct-p/PowerApps1