WordPress function to add text warning on every pages [closed]

Where do you want it to appear?

this function will put something before, or after, the content of each page.

function rt_before_after($content) {
    $beforecontent="This goes before the content.";
    $aftercontent="And this will come after.";
    $fullcontent = $beforecontent . $content . $aftercontent;

    return $fullcontent;
}
add_filter('the_content', 'rt_before_after');

If you want it somewhere in particular let me know where you want and I’ll provide other options.