Autodesk.Revit.DB.Events.DocumentCreatingEventArgs is a class that represents the arguments for the DocumentCreating event in Revit.
The DocumentCreating event is raised when a new document is being created in Revit. This event provides an opportunity to initialize properties or perform other actions on the newly created document.
private void OnDocumentCreating(object sender, DocumentCreatingEventArgs e)
{
// Access the newly created document
Document doc = e.Document;
// Set some document properties
doc.Application.Username = "John Smith";
doc.Application.CompanyName = "ABC Engineering";
}