I would like to know if I can use our own server for application of monday.
Hello there @TIIIIK and welcome to the community!
I hope you like it here 
If the question is if you can use your own local server for the backend of your own app, then yes. You can.
If the question is if you can run our platform directly in your own server, then no. That can not be done.
Let me know if you have any other questions 
Cheers,
Matias