$foo = 'hello world!';
$foo = ucwords($foo); // Hello World!
$bar = 'HELLO WORLD!';
$bar = ucwords($bar); // HELLO WORLD!
$bar = ucwords(strtolower($bar)); // Hello World!
//With custom delimiter
$foo = 'hello|world!';
$bar = ucwords($foo); // Hello|world!
$baz = ucwords($foo, "|");