Which email etiquette is necessary when composing an email?
. the
must be correctly filled to reflect the
the email must include a courteous greeting and a
purpose or intent of the email.

subject, purpose and the recipient details

Explanation:

The email should have a good subject, and that means it should be precise but should convey the purpose and the recipient details. And the detailed report is to be mentioned in the actual body of the email. However, always ensure that the purpose or intent and the recipient details are being mentioned in the subject itself such that the recipient understand in a second the purpose of the email, and also that it meant for him/her.