If executed without any arguments (just 'SetPlayerRace'), the race menu will be opened, allowing you to customize your character's race. Otherwise, this command will change the race of your character to the race with the specified ID.
setplayerrace [race id]
| Race ID | Optional - if you do not provide this argument, the race menu will be opened. The ID of the race to set your character to. |
SetPlayerRace nordrace
The above command would make your character a nord.
ShowRaceMenu
This is an alias of SetPlayerRace - it has the exact same function.