hello,
did you buy a new computer ?
many new computers come with pre-installed mcafee on device. the popup you noticed is marketing of threats that are out there and antivirus is to recommend.
normal you have a 30day trial period available but for that time of period you have to register. otherwise it is a few days only for trial time.
if mcafee is something of your liking is up to you by using the trial period.
i have article from pcmag.com about test review of Total Protection. (Livesafe)
McAfee Total Protection Review | PCMag
hope this helps you a bit ?
greetings