customize

customize is an interactive autoloaded compiled Lisp function in `cus-edit.el'.

It is bound to <menu-bar> <options> <customize> <customize>.

(customize)

Select a customization buffer which you can use to set user options.
User options are structured into "groups".
Initially the top-level group `Emacs' and its immediate subgroups
are shown; the contents of those subgroups are initially hidden.