Create folder if it doesn't exist: the right way in PHP

Hello everyone! I'm new to PHP and trying to make a simple CMS on WordPress. I need to create a directory by date when uploading images to the server, for example /uploads/2024/03/. But I keep getting the error "failed to open stream: No such file or directory" if the folders don't exist yet.

Here's my current code:

$path = '/var/www/html/uploads/' . date('Y/m');
$file = $path . '/image.jpg';

// Trying to save the file
file_put_contents($file, $data);

I already tried using mkdir($path) before writing, but the folder still isn't created. I googled it — people say I need to check for existence. I added a check:

if (!file_exists($path)) {
    mkdir($path);
}

But now I get the error "mkdir():