Hello,how can i get rid off endpoint firewall pop up from main screen ?

I used the activity monitor to terminate the "endpoint security firewall" service, and then I could delete only the firewall app in Finder/applications by dragging it to the trash.

I kept the VPN client, though, as I only needed that one.

Uninstall the app.

Or try turning off Its notification in System Preferences > Notifications.

You already have a built-in firewall, why do you want two?

shut the app down and drag it form the Applications folder to the trash and empty the trash. You may need to start up in safe mode to do this.

But if it came as a "package" I suggest you talk to your school and do as they instruct.