By `Lex Li`_
Sphinx supports a few underline characters that can be used in section headers, such as '=', '-', ':', '.', ''', '"', '~', '^', '*', '+', and '#'.
Though '`' and '_' are also valid in Sphinx syntax, the syntax file used by this extension does not work well with them. So these two are not supported by this feature.
The keyboard shortcuts are,
ctrl+k ctrl+=(on Mac
ctrl+k ctrl+-(on Mac
cmd+k cmd+-) (in reverse order, 78.0.0+)
To learn all keyboard shortcuts of this extension, please refer to :doc:`/articles/shortcuts`.
Pressing the shortcut key would convert the current line under the cursor to a section, by adding adornment (underlines below the title text).
Pressing the shortcut key multiple times switches among the adornment characters.