/name by itself will make your name invisible to other players.
/name [firstname] [lastname] will change your displayed name to the one you entered.
Whether this changes the server name directly or sets a nickname (stored in the database) depends on the configuration settings.
/nameop
Command to open the UI for detailed name settings.
/allname
Command to hide all player names from your own view.
Using this can help reduce performance load in high-load situations.