How to Hide Metabase - Post Meta and User Meta Editor Meta Boxes

function plt_hide_metabase_post_user_meta_editor_metaboxes() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Hide the "Meta" meta box.
	remove_meta_box('metabase', $screen->id, 'advanced');
}

add_action('add_meta_boxes', 'plt_hide_metabase_post_user_meta_editor_metaboxes', 20);

Where do I put this code?