After the Leaky Cauldron hub area is unlocked, enter Wiseacres Wizarding Supplies in Diagon Alley before starting actual game play. Go upstairs and talk to the vendor, then enter one of the following passwords to activate the corresponding cheat:

Spells
CHEAT FUNCTION - CHEAT CODE
Accio - VE9VV7
Engorgio Skullus - CD4JLX
Stupefy - UWDJ4Y
Trip Jinx - YZNRF6
Flipendo - ND2L7W
Incarcerous - YEB9Q9
Glacius - ERA9DR
Herbifors - H8FTHL
Anteoculatia - QFB6NR
Calvorio - 6DNR6L
Colovaria - 9GJ442
Redactum Skullus - UW8LRH
Locomotor Mortis - 2M2XJ6
Tarentallegra - KWWQ44
Entomorphis - MYN3NB
Rictusempra - 2UCA3M
Multicorfors - JK6QRM
Slugulus Eructo - U6EE8X

Bricks
CHEAT FUNCTION - CHEAT CODE
Gold Brick 1 - QE4VC7
Gold Brick 2 - FY8H97
Gold Brick 3 - 3MQT4P
Gold Brick 4 - PQPM7Z
Gold Brick 5 - ZY2CPA
Gold Brick 6 - 3GMTP6
Gold Brick 7 - XY6VYZ
Gold Brick 8 - TUNC4W
Gold Brick 9 - EJ42Q6
Gold Brick 10 - GFJCV9
Gold Brick 11 - DZCY6G

Cheats
CHEAT FUNCTION - CHEAT CODE
Silhouttes - HZBVX7
Ice Rink - F88VUW
Disguise - 4DMK2R
Carrot Wands - AUC8EH
Singing Mandrake - BMEU6X
Character Token Detector - HA79V8
Fall Rescue - ZEX7MV
Character Studs - H27KGC
Score x2 - 74YKR7
Score x4 - J3WHNK
Score x6 - XK9ANE
Score x8 - HUFV2H
Score x10 - H8X69Y
Stud Magnet - 67FKWZ
Regenerate Hearts - 89ML2W
Extra Hearts - J9U6Z9
Invincibility - QQWC6B
Red Brick Detector - 7AD7HE
Hogwarts Crest Detector - TTMC6D
Gold Brick Detector - 84QNQN
Christmas - T7PVVN
Fast Magic - FA3GQA
Fast Dig - Z9BFAD