Final answer:
The subject line states the reason for an email and should be clear and meaningful to catch the recipient's attention. It is the first indication of the email's content and importance.
Step-by-step explanation:
The subject line states the reason for an email message. It is essential that the subject line be clear and meaningful to grab the recipient's attention and ensure that your email stands out among many others that the person may receive. A good subject line also makes it easier for the recipient to prioritize and reference the email at a later time. The first few sentences of your email should then reiterate the purpose stated in the subject line, but in a more detailed fashion within the body of the email.