main site SEO settings

Hello, I am using Semper Fi Lite for my theme, and the address is
http://www.cen-texcraneservice.com
I am trying to figure out how to edit the SEO, keywords for my site. I’m able to edit each page but can’t seem to find where I edit this information for the site itself.
Thank you in advance for your help.
Regards,
Carolyn

https://wordpress.org/plugins/google-sitemap-generator/