Do I have a virus on my MacBook Air?

I will not click on your link but in general, do not install third party apps that claim to protect, clean, manage, boost performance, etc. These apps use system resources while providing no benefit. And they may cause problems.

What makes you think you may have a virus?

enigma32562 wrote:

Does anyone have experience with in relation to using Avast

Yes. It's junk. Rule 1 of Macs is don't install junk.