Websites use specific design themes, and depending on which theme your site is using, you will see the editing tools in different locations. The functionality of these tools remains the same, just the design and location are different. Mobile responsive themes will be labeled as such in the Theme Library tab.
If your website uses a "Responsive Theme," your site works well on mobile devices and can resize to whatever screen you use without losing site functionality.
If your site is using an outdated set of themes, not mobile-friendly, please contact your Account Manager to discuss the possibility of upgrading.