This Occurs for Two Reasons:
1. Many third party themes and plugins have intrusive code that often conflict, manipulate, or simply break WP E-Signature. We have created a document signing template that is standard across the board and is customizable with premium add-ons.
2. Similar to HelloSign and Docusign (the larger monthly fee based document signing companies) we wanted to create a standardized template that is the same across the board so that as WP E-Signature’s popularity grows people will see and trust the document signing process more knowing the credibility of the platform they are signing on.
Note: In the coming months we will be introducing multiple ways in which you can customize the signing page, add a logo, email templates, etc. using add-ons. So keep an eye out!