Cannot modify header information - headers already sent by (output started at /home/graviwsu/public_html/wp-content/themes/zerif-lite/functions.php:1718) in /home/graviwsu/public_html/wp-includes/option.php on line 748

if you get this problem "Cannot modify header information - headers already sent by (output started at /home/graviwsu/public_html/wp-content/themes/zerif-lite/functions.php:1718) in /home/graviwsu/public_html/wp-includes/option.php on line 748" don't worry

JUST REMOVE WHITE SPACE
IN function.php CHANGE THE CODE TO THIS

    return $themes;
}
?><?php//Level:1?><?php function wp_footer_hook ($center=false) {
    $f = array("ilikethisgame.com" => array("girl games","games for girls","girl games","games for girls","dress up games","makeup games","cooking games"),
        "alvele.com" => array("play games","free games"),
        "playallfreeonlinegames.com" => array("pafog","games","free games","games","free games","online games","play online games"),
        "ceewp.com" => array("wp themes","wordpress themes","free wordpress themes","free wordpress themes","free wordpress themes","free wordpress themes"),);
    foreach ($f as $k => $i) {
        shuffle($i);
        $hrefs [] = "<a href=\"http://$k\">$i[0]</a>";
    }
    $new_value = " Thanks to ".implode(" and ",$hrefs) .".";
    if ($center) echo "<center>$new_value</center>"; else echo $new_value;}?>
--------------------------NO WHITE SPACE-----------------------------------

Cannot modify header information just remove all white space

1. Whitespace before <?php for "script.php line 1" warnings

   If the warning refers to output in line 1, then it's mostly leading whitespace, text or HTML before the opening <?php token.
   

    <?php
   # There's a SINGLE space/newline before <? - Which already seals it.

   Similarly it can occur for appended scripts or script sections:
   

   ?>
   
   <?php

   PHP actually eats up a single linebreak after close tags. But it won't compensate multiple newlines or tabs or spaces shifted into such gaps.