The document discusses transforming full-trust solutions in SharePoint to the add-in model or SharePoint Framework. It outlines the major changes required like moving from the server-side object model to the client-side object model and REST, avoiding declarative artifacts, and approaching SharePoint as a service. The transformation process involves assessing existing customizations, learning new techniques, planning the solution, and tracking progress. It recommends reimagining the solution instead of just copying code and discusses resources like the SharePoint Pattern and Practices and SharePoint Framework for developing solutions in the new models.