Add A Meta Description For A Custom Post Type Archive In WordPress

Here's my issue :
I have a WordPress site where I created a custom post type (named "collections") with an article for each collection.
I'd like to add a meta description to the archive page of the custom post type

I have tried with this bit in header.php :

if (is_category('collections'))
    <meta name="description" content="the description">
<?php } ?>

but there's nothing in the source code...
I have looked everywhere in Yoast SEO but I can't find a solution, not even on google. Do you have ideas ?



If you want to check post_type archive page then you have to use is_post_type_archive() and if you want to check the archive page of custom post_type category then you have to use is_tax()

if (is_post_type_archive('collections'))
    echo 'This is the collections post_type archive page';

Addition info but not directly related to your question.

if (is_tax('collections_cat', 'cat-1'))//<-- Replace it with your taxonomy, term name
    echo 'This is the collections post_type, category cat 1 archive page';

Hope this helps!