The simplest path to add signature to your emails is:
- Put your logo or other images in the media manager;
- Access the [Website & Template Manager > Templates > E-mail Templates] menu;
- At the left side, select the [SUB-TEMPLATES] section and create a new one with a friendly name (e.g. footer);
- Edit the content of the signature;
- Save the changes made.
From this action, your sub-template will be a variable in the other types of email and you just need to apply it to the content of the other emails: