Instructions
Turn on your PlayStation 3.
Choose "PlayStation Network."
Open the "Account Management" option. Select the button reading "Name."
Input your clan tag before your actual user name using the PlayStation 3's virtual keyboard. If your clan is named "Clan1," for example, you would type "Clan1" followed by a space followed by your actual user name.
Press the "Circle" button on your controller to save the addition of your clan signature and return to the previous menu.