The local SIM Card in India gets you an entry to important services in the country : shopping, ordering taxis, food delivery, maps, internet, connecting with your hotels or tour operators – you name it.
Make sure your phone is unlocked to any network before you fly to India. Usually you can just call your network provider to request this; sometimes there is a cost. Iphone usually requires this.
You have an option of buying the Indian SIM at the kiosk in the airport of your arrival to India or at a local retailer at the nearest town.
It is also recommended to carry a universal plug adaptor.
You need to have the following documents to buy a SIM card in India:

• Original Passport
• Photocopy of passport and visa (big offices usually do it on spot by themselves)
• Passport picture (2-inch x 2-inch)

Sometimes you can be also asked for:

• Local reference number (You can provide our cell no here )
• Address proof in your country of residence (utility bill, ID Card, driver’s license)/li>

Usually, the sim card gets activated in a few hours time.