Using eform or another solution for uploading a file

     if($_FILES['mp3']['error'] == 0 ){
        //unique file name
        $un = uniqid();
        //move file to files/mp3 folder
        move_uploaded_file($_FILES['mp3']['tmp_name'], 'assets/files/mp3/' . $modx->getLoginUserName() . '-' . $un . '.mp3');
        
        ....... more code
        
    }else{
        return false;
    }