To email the active document as attachment, click the Send document by email toolbar button, or choose the "File | Email | Send by Email..." menu command.
To send all open documents as attachments of the same message, choose the "File | Email | Send All by Email..." menu command.
To zip the documents and attach them to a new email message, ready to be sent in your default mailer, choose the "File | Email | Send by Email Zipped..." or "File | Email | Send All by Email Zipped..." menu commands.
Note that in order to be able to email documents from within Atlantis as attachments, you need a MAPI-compatible email client on your system, like Mozilla Thunderbird.
To email the contents of a document not as attachment, but as a direct email message: