Add custom post types to archives in WordPress

functions.php

<?php

// Add custom post types to archives
function namespace_add_custom_types( $query ) {
    if( is_category() || is_tag() && empty( $query->query_vars['suppress_filters'] ) ) {
        $post_types = get_post_types( '', 'names' );
        $query->set( 'post_type', $post_types);
        return $query;
    }
}
add_filter( 'pre_get_posts', 'namespace_add_custom_types');