In Enterprise Architect a model is a special type of package, being the top level entry point to an Enterprise Architect project file.
You can develop a project with one model, or with several. Each model is a root node of a hierarchy of Model Packages and Views and, below them, packages. A model contains the diagrams, elements, relationships and associated metadata that define the structure and function of a system or process. These components are organized through the package hierarchy, which helps to group and manage related components. By iterating through all models, you can access all the elements within the project.
You can create the model or models when you first create the project, or you can add and develop new models later. You can also delete a model, but be aware that everything contained in the model is deleted as well.