Get WPSEO title and description for category, taxonomy archives, pages, posts

gistfile1.php

<?php
// access wpseo_frontend class and get the seo title and seo description for output on archive pages
if ( class_exists( 'WPSEO_Frontend' ) ) {
	$wpseo_object = WPSEO_Frontend::get_instance();
	$headline = $wpseo_object->title( false );
	$intro_text = $wpseo_object->metadesc( false );
}
$headline = sanitize_text_field( $headline );
$intro_text = sanitize_text_field( $intro_text );

// these should work if not archives
# $headline = get_post_meta( $post->ID, '_yoast_wpseo_title', true );
# $intro_text = get_post_meta( $post->ID, '_yoast_wpseo_metadesc', true );