System settings contain the basic and advanced settings of your website. The menu contains the following items:
Settings: domain, culture, display name, SMTP and custom fields
Site users: users and their role in this site.
Custom errors: custom error pages of your site.
Url redirects: redirects to map old URL to new URL
Robots.txt: Rules used by search engine to crawl your websites
System diagnosis: assessments of your system's health