Sending a Document as a Message
Sometimes you may need to send documents to people outside your project team to sight and review. To do this, go to your Projects list and click on your project. You will see a menu with folders and deliverables.
Documents can be located within projects or deliverables. Use the menu to toggle to go to the correct project, sub-project or deliverable. Then scroll down to the Documents section on the resulting page.
To send a document as a message, select its checkbox and click the Message icon 
from the bar that runs across the top of documents collection.
This section shows your most recent documents only. If you cannot see your document, click the blue square button to show all documents stored for a given project or deliverable.
The Actions bar is also useful when you have multiple documents to delete, to send for approval or if you have multiple documents to edit. Note that external links aren't eligible for batch actions.
Sending a Document as a Message
From the resulting page, you'll be able to create your message and add your content. Like an email, you'll be able to type in a name to send your message to an existing user. The document(s) will be appended to the attachments section of this message by default.
Once you're happy with your inputs, click Submit to send your document off.