The first one, the recipient-specific footer, you are able to edit
For products go to Configure > Advanced Settings > Add a Prefix & Add a Footer settings
For lists go to Configure > Advanced Settings > Add a Prefix & Add a Footer settings
The second one at the end of your email, the legal footer, is auto-generated by Simplero and cannot be edited.
You can edit the background color of both the footers though. You do this in your email template if you use the Simple template.