If you are a Vodafone Idea Vi customer then using Short codes or USSD Codes..
On your Vodafone mobile phone if you want to speak to multiple people at once..
If you are a Vodafone Idea Limited VI customer then Vi has started WhatsApp Customer..
If you are Idea mobile network customer then currently Idea is offering its customers free..
If you are a Indian mobile customer and would like to know the call history..
If you are an Idea cellular customer and would like to know who has called..