Final answer:
A file that comes with an email message is known as an attachment. This file can be a document, image, or other types of media, and is represented by an icon in the email client.
Step-by-step explanation:
A file accompanying an email message is called an attachment. When you receive an email, any additional files that come with it, such as documents, pictures, or videos, are called attachments. These attachments are usually indicated by a paperclip icon or similar graphic in your email client, signifying that there's more to the email than just text. To view or download the attachment, you typically click on the icon or the name of the file.