Site-wide HTML signature files are stored in a folder called Signatures in the shared PRS data folder.
If you don't install a custom HTML signature file a built-in default signature is used.
Use the HTML Signature command to create and edit a custom HTML signature. The HTML Signature command saves the signature in the Signatures folder with the file name mail_template.html. If you have an existing signature file you can install it by coping to the Signatures folder and naming it mail_template.html.
You can add a picture to HTML mail messages using the HTML Logo command to select an image file (GIF, JPEG or PNG format). The HTML Logo command copies the image file to the Signatures folder and names it mail_logo with the appropriate file name extension. The image will be positioned at the {logo} placeholder in the HTML signatures file (or at the end of your message if there is no {logo} placeholder).