To download and install McAfee on your Mac, start by visiting mcafee.com/activate to get your activation code. Once on the site, sign in to your McAfee account or create one if necessary. After logging in, download the McAfee installer for Mac. Open the downloaded file and follow the on-screen instructions to begin the installation process. You may need to grant permission for McAfee to install its software on your Mac. Once installed, open McAfee and enter your activation code from mcafee.com/activate to complete the setup. Regularly update McAfee to ensure your Mac stays protected.