What icon is usually used to indicate an attachment feature?

An icon is a symbolic representation of an action to be taken, given in emails or message bars. Icons are metaphorical representations of emotions and feelings which a human is unable to explain in words.

The icon used to represent an attachment is paper clip.

When we click this paper clip icon, it allows us to attach any file including a document or a picture in that particular email. An attachment may also contain a virus, Trojans, worms and other form of malware.