A signature template is an Outlook signature file with one exception: Fields you want to populate from Active Directory are represented by special scan codes recognizable by Adolsign.
Outlook supports three signature formats: HTML, rich text and plain text. Format type is configurable via mail format settings in Outlook (example below is from Outlook 2003):
You need only to create signature templates for the message format you use in Outlook. As an example, if your Outlook is configured to send messages in plain text, all you need is to create a template in plain text and save it with the .txt extension. Extensions .htm and .rtf are used for HTML and rich text signature templates respectively.
You can use any text editor to create plain text signatures (txt). Microsoft Word is the best tool for rich text based signatures (rtf). While Word is also a viable option for creating html signatures, it is too noisy! As an alternative, you may consider to use free html editors available.