$re = '/\bUA\s?\d{2}\s?\d{6}\s?\d{19}\b/m';
$str = 'UA 19 300346 0000000000029242108
UA193003460000000000029242108
UA 193003460000000000029242108
UA293003560000000000029112108
UA083001260000000000029243308
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php