Latest WhatsApp beta version lets you add contacts through QR Code. By using this feature you can make QR code for your personal Whatsapp number and your friend can send WhatsApp message by scanning your QR code. This feature is available in the latest beta version v2.20.176. To get this you need to update your Whatsapp to latest beta version from play store. If you don’t get the latest beta version from Play Store then you can get it from here.
Click Here to Download Latest Beta Version
How: You can Add Contacts through QR Code Scanning in Whatsapp