Once signed in you'll see your site, or a list of websites that have been verified using Google Webmaster Tools.
A list of Users and Site Owners will appear. There are two types of users that you can add to your Google Webmaster Tools account: Restricted and Full.
Site owners always have complete control over all settings in Webmaster Tools. A Full user can change most settings and take most site actions like submitting a new URL to Google's search index. Restricted users in Google Webmaster Tools are generally restricted to view only permissions.
Be Careful of who you give full access to. Google Webmaster Tools are powerful and can have a significant impact on improving or ruining your Website's performance.