Below is best practice for emailing a CSD document like an invoice.
Go to Order Inquiry in CSD and enter your order number. Then click Search. After clicking Search and displaying your order, click the side bar widgets icon to bring the side bar into view. Then scroll to Related Information v2. Click the drop down arrow in the box that says All and select OrderEntryHeader. Once your document is displayed in the widget click on the little icon to show in IDM. This will open a CSD tab called Document Management. Once in Document Management you have the option to Send in email. Click that to bring up a window to enter an email. (NOTE: you can search other document types using the search bar in top left.) With the email prompt you can send to any email address, fill in any subject and include a message. Then click Send. This concludes the emailing process.