To log in to WhatsApp Business Web, here are the steps you need to follow:

1. Open your web browser on your computer and go to web.whatsapp.com.
2. Open the WhatsApp Business app on your mobile device.
3. In the WhatsApp Business app, tap the menu icon (three dots) at the top right corner.
4. Tap on "Linked Devices" or "WhatsApp Web".
5. Tap on "Link a Device" to open the QR code scanner.
6. Use your phone to scan the QR code displayed on the web.whatsapp.com page on your computer.
7. Once scanned and authenticated (you may need to enter your password or use biometrics), your WhatsApp Business account will be connected to the web browser.

Note: This login session remains active as long as you keep the browser open and your mobile device connected to the internet, unless you use multi-device mode. You can then start to manage your business chats and customer conversations directly from your desktop browser without the need to download any additional software. If you prefer, there are also desktop apps available for Windows and macOS that provide similar functionality, using the same QR code login process. This process helps you use WhatsApp Business efficiently on a larger screen and allows faster customer interaction.