You can activate your EA Activation Key via downloading the EA Client App for your PC or via the Electronic Arts website. 

Via App: 

1. Select the My Collection and click on Redeem Code.
   
   
2. Enter your activation key in the dialog box and ensure that you’ve left no empty spaces before or after the code
   
   
3. Click on Next and enjoy!
   
   

EA Website: 

1. Log in to your account and go to the accounts page. 
   
   
2. Click on the Redeem Code option and enter your activation code. 
   
   
3. Click on Next and enjoy!