After redeeming your McAfee retail card at mcafee.com/activate, you can download and install McAfee software and activate subscription. For this, you can First, visit www mcafee com activate. Enter your activation/product key, Login or create a new McAfee account. Download and install McAfee antivirus software on your PC or Mac. Now, your McAfee security will be activated on your PC or Mac. Note: If you have already used your activation code, click Download Your Antivirus Software.To find out 25-digit McAfee Activation code before visiting mcafee.com/activate. If your McAfee product is a retail version, Look for 25-digit activation key on your purchased retail card. Or if you bought online, you receive it in your email that you used at purchasing time.