Steam is a program developed by Valve to let gamers purchase and store their computer games digitally. In order to maintain a library of Valve computer games, you must create a Steam account and choose a username and a password. If you want to keep your username private, you can choose to display an alias. This can only be done within the Steam program, not on the store or community websites.
Click "Steam" in the toolbar and select "Preferences."
Click the "Friends" tab.
Type your desired alias in the text field under "Profile name." This is the first item, listed at the top of the menu.