Well if you just installed Ubuntu 14.04, you should figure this out already.
You will notice that your name is not displayed on the indicator bar, in the right top corner of the desktop. If you still want enable it; this is very easy to do.
Open Terminal and run the command below:
$ gsettings set com.canonical.indicator.session show-real-name-on-panel true
To hide the name, just replace true with false in the above command:
$ gsettings set com.canonical.indicator.session show-real-name-on-panel false