Optimizing your Open Graph tags
Editing Open Graph info for pages
By default, WordPress do not have an option for excerpts. And excerpts are what are displayed in the "Description" Open Graph meta tag.
Add this line of code to add the excerpt option to your WordPress pages:
add_post_type_support( 'page', 'excerpt' );
Now you can edit the content of the "Description" Open Graph meta tag for pages.