First you must go to the game folder and find the file named nwn.ini Now open this file in Notepad and go to the Game Options section, and add the following:

Debug Mode=1

If you are going to edit the characters, open the nwnplayer.ini file and add these lines:

Single Player Enforce Legal Characters=0
Single Player ItemLevelRestrictions=0

This allows you to play past the module you're on.

Now save the file and start the game. During the game hit the tilde (~) key to bring down the console. Now type DebugMode=1 . Cheat mode is now enabled. Cycle through the codes with the tilde (~) key. Use any of the codes below. If you get a message that says Enter Target Mode Appears, click on the character you'd like the code to affect.

Change age: SetAge (number)
Change base attack SetAttackBase (number)
Change Charisma: SetCHA (number)
Change Constitution: SetCON (number)
Change Dexterity: SetDEX (number)
Change fortitude save modifier: ModSaveFort
Change Intelligence: SetINT (number)
Change Level: dm_givelevel (number)
Change race: SetAppearance (race)
Change reflex save modifier: ModSaveReflex
Change spell resistance modifier: ModSpellResistance (number)
Change Strength: SetSTR (number)
Change will save modifier: ModSaveWill
Change Wisdom: SetWIS (number)
Flying Cows: dm_cowsfromhell
Get Gold: dm_givegold (number)
Hobby Horse: dm_mylittlepony
Invincibility: dm_god
Restore HP: dm_heal
Raise levels: GetLevel (number)
Raise XP: GiveXP (number)