I have a wpf mvvm application, where do I put Database or Sockets?

as I explained in the title I have a wpf app with only one View. The model is Note. In the view you can add notes. Those notes must be sended to a sockets server or saved on a Database, my question is: where do I put the code related to the action of saving notes? In model, viewmodel or in another class?

This question may be trivial, but I have just started up with wpf+mvvm and I am a bit lost.

Thanks for your help :)