you have to enable mbstring to use the multi bytes functions go to this website and follow the instructions : https://www.knowledgebase-script.com/kb/article/how-to-enable-mbstring-in-php-46.html
<?php $str = "mary had a Little lamb and she loved it so"; $str = mb_convert_case($str, MB_CASE_UPPER, "UTF-8"); echo $str; // Prints MARY HAD A LITTLE LAMB AND SHE LOVED IT SO $str = mb_convert_case($str, MB_CASE_TITLE, "UTF-8"); echo $str; // Prints Mary Had A Little Lamb And She Loved It So ?>