Despite its proven pervasiveness and effectiveness, the role of email in political campaigns has been understudied. In this article, we seek to understand the use of emails by Donald Trump's and Joe Biden's campaigns during the 2020 U.S. presidential election. Employing newly collected email data (N = 4051), we compared how the two campaign teams differ in the use of appeals in their emails, and the functions of the message (e.g., attack, acclaim). We found that, while both campaigns used emails primarily for fundraising, Trump's campaign (compared to Biden’s campaign) was more likely to use all of the four appeals we defined — material, solidarity, ideology, and issue appeals. We also found that by sending emails, Biden's campaign tends to acclaim itself more while Trump's campaign attacks opponents more.