How to stop McAfee and Microsoft popups

Looks like you're on Desktop instead of Android, so I'll move your question accordingly.

To your question about pop ups, you may want to check out the following article: Web Push notifications in Firefox.

I had these with McAfee. I was typing a micrsoft word docx, when the popup disappeared. Possibly they are timed out. But see Trust Pilot on this product. Company that size using scare-ware! Thr answer may be to wait a few days and see if it goes.