In most situations, we refer to people by their first name. It’s not rude to write an email to someone you’ve never met and automatically call them by their first name. In business settings, it’s often on a first-name basis, likely even with your boss. To give an idea of how ...
For example, a casual email to a friend could simply say “What's Up?” If you are emailing with a question about an assignment, though, the subject line might read something like “Math homework.” Similarly, a question to a supervisor or professor could be labeled with a subject line ...