add_filter( 'jnews_dropdown_link', 'jnews_child_dropdown_link' );
 
function jnews_child_dropdown_link( $dropdown )
{
    //For add submenu
	$item = array(
		'new_submenu' => array(
	        'text' => esc_html__( 'New Submenu', 'jnews' ), //your menu name
	        'url'  => '#' //the url
	    ),
	);
 
    if ( isset( $item ) ) 
    {
        $dropdown = array_merge( $item, $dropdown );
    }
 
    //For remove submenu
    //unset($dropdown['edit-account']);
 
    return $dropdown;
}