How do political campaigns choose who to decide the email is from?

We all know that Barack Obama and Joe Biden are not sitting down and writing emails to us. I get emails that say they are from Obama, Biden, campaign staffers, etc. Is there reasoning behind which emails come from who? As the reader, I honestly don’t really care because I know that it’s a staffer writing and sending all of them. I don’t get excited when I see that Barack wrote me an email! If he REALLY wrote ME an email I would! (by the way, after his speech at the DNC 4 years ago I wrote him an email saying he should run for president. He never wrote back!)