Emacs provides extensive help features accessible through a single character, C-h. C-h is a prefix key that is used only for documentation-printing commands. The characters that you can type after C-h are called help options. One help option is C-h; that is how you ask for help about using C-h. To cancel, type C-g. The function key F1 is equivalent to C-h.
C-h C-h displays a list of the possible help options, each with a brief description. Before you type a help option, you can use SPC or DEL to scroll through the list.
C-h or F1 means ``help'' in various other contexts as well. For example, in query-replace , it describes the options available. After a prefix key, it displays a list of the alternatives that can follow the prefix key. (A few prefix keys don't support this because they define other meanings for C-h.)
| 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). |
| Misc Help | Other help commands. |