Hello, @Sekhar,
Thanks for using our theme.
1.. Use SEO plugin to add more/edit options for FB share, for example, Yoast SEO plugin.
2.. Use SEO plugin to add the necessary OG image and OG description for your pages, posts, products. Try for example Yoast SEO plugin.Don’t forget to clean the Whatsapp cache for the posts
I hope you understand.
Regards 8Theme Team.