How to create a new model at the moment when form is saved

This is not something that the Django ORM supports. It’s expecting all models and their underlying tables to exist at the time the system is started.

If you wanted to completely manage the creation and access to those tables directly through raw SQL, you could write something to implement that, but that’s going to need to effectively bypass Django.

Also see Trouble creating a module and the threads referenced by it for some additional information.