Your page's meta description is a meta tag that gives potential site visitors a summary of what your page is about. It is not visible on your site's page, but appears below your page's title tag in search results.
To change a page's meta description:
Click Menus & Pages on the left side of the Editor.
Click the More Actions icon beside the relevant page.
Select SEO Basics.
Enter the page description under What's the page's meta description (description in search results)?.
Publish your site.