Installation

The app requires you to have Whatsapp Business app installed on your smartphone. You can use an Android or iOS device.
Install the OAPPS for Whatsapp app from the LiveChat marketplace. The app is only available for the new user interface.
The settings page will open after you the app is installed. Alternatively, go to the application page in the Marketplace and open the application setup menu.

Enter your company name.
Paste your e-mail address.
Open WhatsApp Business application on your phone.
Tap dots ⠇ in the app's right top corner (Android) or Settings (iOS) and go to WhatsApp Web/Desktop.
Scan a QR code on app's page.

If the connection is successful, you will see this section:

Additional details and restrictions

You must have a WhatsApp account. Install the WhatsApp™ Business app from Google Play or App Store to get an account. We recommend using a dedicated phone number for WA customer support.
Only one Web connection is possible at the same time. Connecting via Web WhatsApp to your WA Business app will interrupt LiveChat connection. Interference is possible.
Note: You can use a personal WhatsApp account for tests, but you must use WhatsApp Business per WhatsApp policy.
Your phone must be online all the time. Otherwise, messages can be delayed or lost.
Note: We recommend connecting the phone to a charger, turning off the power saving mode, and other functions that may interfere with the application.
Only your customers can initiate contact. You can't reach them proactively with the app (as per WA T&C)
WA Calling is not supported, only messages. You still receive calls via WA Business app on your phone.
Some media that users send you won't be displayed in LiveChat interface. You may get a Security threat notice.

This will happen for video messages (.mp4) and voice messages (.ogg). Press [Discard] to get the message.

To unpair the phone, press Go to app settings

Locate and press [Unpair] Now you can connect another phone

You can connect more than one Whatsapp phone for an additional fee.

You can assign new chats to specific groups in account settings.

Publish your contact number via a deep link on your web page or social media. The link format is

whatsapp://send?phone=+**your phone here**
e.g. our contact phone is
whatsapp://send?phone=+79164431858

if a user clicks the link on his mobile, the WhatsApp app will open.

Go to WhatsApp Busines settings -> Short link and use the short link provided.

Also, using a method described here you can set up a button like this:

You can set up a greeting message in your WA Business app
For Android: https://faq.whatsapp.com/en/android/26000100/?category=5245246