Looking for a solution to forward mails using procmail, e. g. the mail will be received as single user using fetchmail ... e. g. a mail to example@mails.com should after the fetchmail process be forwarded to example@mails.com

This can be done using procmail as far as I know ... so the procmail process should just do: Get recipient adresses from To, CC, BCC and send mail to those (and not to the user who uses fetchmail to catch all the mails).

I think this somehow works if you have in your .fetchmailrc something like
mda "procmail -d"


Can somebody help me to set up the procmailrc ?

Not that I can't ship a readymade recipe your way in 5 secs, but wouldn't it be more satisfying for yourself if you read the procmailrc manual, try to build a recipe, try it out (add "verbose=on" and logfile=</path/to/filename>), and post here when you try to fix errors?