You can use the Revit Platform API to:
Gain access to model graphical data.
Gain access to model parameter data.
Create, edit, and delete model elements like floors, walls, columns, and more.
Create add-ins to automate repetitive tasks.
Integrate applications into Revit-based vertical products. Examples include linking an external relational database to Revit or sending model data to an analysis application.
Perform analysis of all sorts using BIM.
Automatically create project documentation.