Download and Install WhatsApp on your Mobile Phone or Your PC (Download Blue-Stacks To Access Whatsapp On PC).
Download and install Whatsapp on your device.Now go to receivefreesms.com and select any of the no. Here I will use an Indian Mobile Number.
Enter the number in the required field on Whatsapp. It will take you to the sms verification page. Now go back to receivefreesms.com and click on the number which you have chosen to verify Whatsapp sms verification.
Enter the verification code in WhatsApp verification page. That's it, you are done..
Note:- Some numbers might not work due to the technical error, no problem choose any other number to verify sms verification. The only drawback with this trick is anyone can use the same no. for verification so during those times WhatsApp will ask you to re-verify your number.