It is not the best but it at least give you an idea of what to do

 

 

https://www.apple.com/covid19/

Well, it's better than one posted here a few weeks ago from a joke of an international hospital in Bangkok.

There is no such thing as an online Covid test.

It's a screening test, meaning it'll give you a hint if you should try to get tested. As such, should work. Obviously not a medical test.