org-html-postamble

org-html-postamble is a variable defined in `ox-html.el'.
Its value is

auto

Documentation:
Non-nil means insert a postamble in HTML export.

When set to 'auto, check against the
`org-export-with-author/email/creator/date' variables to set the
content of the postamble. When set to a string, use this string
as the postamble. When t, insert a string as defined by the
formatting string in `org-html-postamble-format'.

When set to a function, apply this function and insert the
returned string. The function takes the property list of export
options as its only argument.

Setting :html-postamble in publishing projects will take
precedence over this variable.

You can customize this variable.