installation and using the mail-app worked out of the box. Thanks.
When sending a mail it is put automatically in the Sent-Folder. This is fine.
Usually I configured my mail to always use BCC to the sending address.
It would be very much appreciated, if such an auto-BCC could be configured.
this rings a bell but I can’t find any existing ticket at https://github.com/nextcloud/mail/issues. Maybe you are more lucky.
Otherwise we don’t have such a feature planned right now.