You can set up and manage your Email Templates within the marketing area of Workbooks (Start > Marketing > Email Templates).  In addition, you can set up Email Signatures within Start > Preferences.  Your default Email Signature will automatically appear on any emails you send from within Workbooks and you can configure Email Templates to append your Email Signature to the template.  Doing this means that you only need to set up one Email Template that can be used by all your Users and will still look personalised when they send it.