For one, you lose the session as soon as you close the browser or tab. However, this method has its share of limitations. Scan the QR code from the mobile app and access your account. You can also use a different browser like Firefox or Opera to open your secondary WhatsApp Web account. All you need to do is open the Incognito mode in your browser, and open WhatsApp Web from there. It is one of the most simple and easiest methods. In a quite similar manner, you can use multiple WhatsApp accounts on PC. You have often used incognito mode on your mobile and PC for regular searches and access multiple accounts simultaneously.