Your clients can attach documents to a message by following these instructions:
Select the blue +Message button in the upper-right corner of the Dashboard.
Select the Message To field to add a recipient and select an Account.
Enter a Subject for the message.
Enter a message by selecting inside the Description box.
Select the paperclip icon in the upper-right corner.
Choose from Browse Files for Upload, or Open Document Scanner.
Rename the file if desired.
Optionally select Add Tags & Year to further categorize the file.
Select Add Attachment.
Select Send in the upper right-hand corner of their screen.