Go to this site: http://www.thesims3.com/
Login to Your Origin Account
Click on Redeem Code in My Page-> My Account menu:
Enter Your code and click Redeem button:
Enjoy your game
Using Sims 3 Code on Origin and Steam: Sims 3 codes are platform-specific, so you can only use the code on Origin, not Steam. You’ll need to purchase a separate copy for Steam.
Code Issues: If your Sims 3 game code isn’t working, check if it's correctly entered, ensure it's valid for your region, or verify it hasn't been used already.
Activating Expansion Packs: To activate expansion packs, follow the same process: in the Origin client, go to "Redeem Product Code" and enter the code for the expansion.
Lost or Replacement Codes: If you lost your game code, contact our Customer Support Representative.