The main software which will make this happen is BlueStacks. It emulates an Android platform on a PC, basically, it enables you to run a majority of Android apps on PC.
The only catch to it is that if you are already using the messaging service on your smartphone you will need another phone number.
To get started follow these instructions:-
i) Download BlueStacks. It is an android emulator used to run android apps on PC, the software is available for Windows and Mac. So we may presume that WhatsApp shall run on Mac.
ii) Search for WhatsApp on it, download it.
iii) Run the downloaded file to install the software.
iv) Give a phone number(not one you’re already using for WhatsApp). You will be given a verification code.
v) Type that code in the verification field.
And you are good to go….easy right? Don’t hesitate to comment if you face any problem.