You will need access (on your system or file server) to the software used to create the attachment. Also, you probably need to be running the same version of the software. If you do not have access to the correct software, you might want to request that the sender convert the file into PostScript format and resend the file.
To view specially-formatted text files:
Copy the attachment into File Manager.
Open the file from the application in which the file was created.
Consult the user manual that came with the application for details.