This is the 3183rd most frequent Spanish word.
adjunto
Attached; enclosed; assistant (depending on context).
Here, 'adjunto' is used as an adjective to describe the noun 'document' indicating that it is attached to the email.
Envió el documento adjunto en el correo.
He sent the attached document in the email.
In this case, 'adjunto' functions as a verb, indicating the action of attaching or including something.
Te adjunto una copia del archivo solicitado.
I am attaching a copy of the requested file for you.
Here, 'adjunto' is a noun indicating a role or position close to or assisting someone, specifically in a professional environment.