This brings up the Emacs FAQ, where you can use the usual search commands (see Search) to find the information.
Finally, you can try looking up a suitable package using keywords pertinent to the feature you need. See Library Keywords.
To find the documentation of a key sequence or a menu item, type C-h C-k and then type that key sequence or select the menu item. This looks up the description of the command invoked by the key or the menu in the appropriate manual (not necessarily the Emacs manual). Likewise, use C-h C-f for reading documentation of a command.
- Help Summary: Brief list of all Help commands.
- Key Help: Asking what a key does in Emacs.
- Name Help: Asking about a command, variable or function name.
- Apropos: Asking what pertains to a given topic.
- Library Keywords: Finding Lisp libraries by keywords (topics).
- Language Help: Help relating to international language support.
- Help Mode: Special features of Help mode and Help buffers.
- Misc Help: Other help commands.
- Help Echo: Help on active text and tooltips ('balloon help')
