Hello, @Lasitha851,
Actually, it is a sub-menu with a mega menu. Our theme has the option to set the mega menu content using static block. I mean you can create a block and add the content in it using the page builder plugin as per your need. Once you created a block you can set that block on a menu item as a sub-item of it. By doing this you can make it.
Check this article for a better reference: https://xstore.helpscoutdocs.com/article/27-mega-menu and here is a video: https://www.youtube.com/watch?v=f07MBdnFPfk&t=3s
Regards 8Themes Team.