Hello. Thank you very much! for OKTOPRINT !!!
I have a question, is it possible that OKTOPRINT is used as an application? Or all the same the Internet is necessary? I use raspberry PI
Octoprint is a stand alone server application, that uses a browser interface for control.
If you are using a Raspberry Pi, then you can down load integrated OS\Octoprint packages that have everything ready to go. This is the Octopi version, more info to be found at OctoPrint.org - Download & Setup OctoPrint
You don't need the internet to use octoprint, but it was designed to remotely control a printer via an internal network, and to be accessed via a web browser.
While you can access octoprint locally on the same machine that's running it, if all you want is local control then I would recommend using Pronterface or Repetier Host.