electron/docs/fiddles/features/window-customization/custom-title-bar/native-window-controls/main.js

const { app, BrowserWindow } = require('electron')

function createWindow () {
  const win = new BrowserWindow({
    // remove the default titlebar
    titleBarStyle: 'hidden',
    // expose window controlls in Windows/Linux
    ...(process.platform !== 'darwin' ? { titleBarOverlay: true } : {})
  })
  win.loadURL('https://example.com')
}

app.whenReady().then(() => {
  createWindow()
})