1) Require electron-windows-badge in your main process:
    const Badge = require('electron-windows-badge');

2) Initialize new object of badge while creating window:
    function createWindow () {
        win = new BrowserWindow({width: 800, height: 600});
        const badgeOptions = {}
        new Badge(win, badgeOptions);
    }

3) To update the badge you just need to call this(you must do it in render process):
    ipcRenderer.sendSync('update-badge', 1);

4) To remove badge just call this(you must do it in render process):
    ipcRenderer.sendSync('update-badge', null);