Professional emails are stressful to write. It's easy to worry about sounding too casual, too formal, or just not knowing what to say. The number of emails sent every second is over 3 million, research shows. With people receiving so many emails every day, writing clear and professional emails has become more important than ever. In this article, we'll break down how to write a professional email, how to start an email, and how to end an email in 2025.