Thank you so much for using our theme SuperMag. It just simple to change the site description and footer text. Please follow this documentation to change them.
Site Description: https://doc.acmethemes.com/supermag/#ManageSiteTitle,TaglineandSiteIcon
Copyright Text: https://doc.acmethemes.com/supermag/#Footeroptions:Howtochangefootercopyright
We have a premium version of this theme with lots of additional features too. If you have time please visit: http://www.acmethemes.com/themes/supermagpro/
If you have any query regarding our theme, please feel free to ask.