The Drafts folder in Outlook stores email messages you've started but haven't yet sent. When creating a new email message, every three minutes Outlook will automatically save it as a draft.  In addition to this auto-save feature, you can manually save a draft at any time, and are prompted to save a message that you attempt to close without sending.

If you want to do any of the following...

• Save a draft of a message that you want to finish later
• Open a message you previously created and saved, and delete it or continue editing it before sending
• Change automatic message saving interval from 3 minutes to anywhere between 1 and 99 minutes
• Turn off automatic saving of unsent messages

... read Save or Don't Save Drafts of Unsent Messages.

If you use Outlook Web Access instead, here's how to work with draft email messages:

Creating a draft:
1. Click the “New” button (this opens a new message window)
2. Address and type the email message
3. Click the “Save” button along the toolbar of the message window
4. Close the message window

Editing a saved draft:
1. Double-click the message to be edited (this opens the saved message)
2. Edit the message
3. Click the “Save” button along the toolbar of the message window
4. Close the message window

Send a saved draft from the Drafts folder:
1. Double-click the message to be edited (this opens the saved message)
2. Update the message (if needed)
3. Add any attachments
4. Click the “Send” button along the toolbar of the message window