Including “Sent from my iPhone” at the bottom of an email signals mobile correspondence, that gives room for an understanding if there is an error in the content. Often, people will forgive you for careless mistakes if they know that the email was sent using a mobile device.
But if you keep aside the series, professionally it’s recommended to use “Sent from my iPhone” as your mobile signature. Author Rob Ashton on his official website writes, “The short answer to the question of whether you should write ‘Sent from my iPhone’ is: yes, you should. Or, at least, you should indicate that you’re sending the message from some sort of mobile device.”
Ashton writes about a research area called uncertainty reduction theory (URT). It’s also known as the initial interaction theory and was developed in 1975 by Charles Berger and Richard Calabrese. It is one of the few communication theories that specifically looks into the initial interaction between people prior to the actual communication process.
“The central idea of URT states that our primary aim in any initial interaction with people is to reduce uncertainty about them. In other words, we want to check that they are what (or who) they say they are, that they have our best interests at heart or that they really will help us having said they would,” explains Ashton.
And, communication is the surest way to reduce uncertainty about a person or situation. People look for cues while communicating, and there are two kinds of cues. One that you can control is called low-warrant cues such as our thoughts and words. The ones that we cannot control easily are called high-warrant cues and “Sent from my iPhone” is one.