XF 1.4 How to put www in front of my domain in Google search (and another question)

Hi everyone,

I run a community and I if someone enters "mydomain.com" in to their browser it remains at "mydomain.com. " but I want it to change to "www.mydomain.com".

Also on Google or other searche engines I want "http://" or "www." in front of my domain to show up.

How do I do these things?