pop up on my phone says my pgine has 11 viruses takes me to a for pay app in apple store

I received a notice which appeared to be from Apple. The notice said that there were 11 viruses on my iPhone 8max. I was advised to click on a link which appeared to take me to an for-pay app in the Apple store. Was the original message from Apple? Is this kind of advertising intrusion allowed by Apple? I checked with Verizon and their (free) app showed no viruses.