The URL resource in Moodle allows you to use a web link in your course site; links can also be added to any other resource or activity type through the text editor (Forum, Assignment instructions, etc).
Adding a link to the main course site
Go to the course homepage and click Turn editing on.
Click Add an activity or resource in the section where you like to add the URL.
Select URL and click Add.
In the Name field, enter a name for the URL.
Optional: enter a description in the Description text box.
In the External URL field, enter a complete link, including http://