General Help

Is there a General Help in lichess?; I can find only lichess.org/faq
I am looking for a description of the features

You can seek help from lichess.org/contact

There are certain options, pick up one of them:

What can we help you with?

I can't log in
I need account support
I want to report a player
I want to report a bug
Appeal for a ban or IP restriction
Collaboration, legal, commercial

I do not know if there is something like a description for the features, but you can contact Lichess and ask your questions in an e-mail.

It's there on Lichess itself

lichess.org/features

to #2 AnonymousChessKing:
e.g. a description for "Advanced Search" - it does not work properly
I will post e new topic in "Lichess Feedback" today

To #4 Beginner_IM
Thank you for the helpful answer!
Where can I find all these links like lichess.org/about, lichess.org/faq, lichess.org/features, …?