Most of the paid software requires a license key or the product key to activate the services of the product in order to avoid all sorts of fraud usage of the program. When the users buy the product from the retailer the product key comes in the form of retail card or on the inner circles of the CD package. And the product key is received in the product confirmation mail, when the product has been purchased via online method. Follow the below procedure in step-by-step order to activate the product:

Explore the Norton.com/Setup product.
Click “Help” option displayed at the top rightmost corner of the main window.
After this, a help center window will appear on the screen.
In the “Account Information” section, select the “Enter Product option” option.
Type the “Product key” in the space provided.
And then, click “Next”.
Now, follow the instruction set displayed on the screen.
At last, click “Done”