I must admit that I have not been paying attention and opened a few of these types of emails on my phone. Fortunately, nothing terrible has happened as most are not designed to work in an Apple OS environment.
In any event, here’s the fastest way to tell. Look at the sender’s true email address. While often spoofing someone sounding credible, the actual email address will quickly reveal the fraud. So, the next time you are contacted out the blue, hover over the email address before taking any action.