Do you have an Electors’ Photo Identity Card (EPIC)?
The Election Commission of India has made voter identification mandatory at the time of poll. The electors have to identify themselves with either Electors Photo Identity Card (EPIC) issued by the Commission or any other documentary proof as prescribed by the Commission.

Will possession of an EPIC alone entitle you to vote?

• You should note that mere possession of an EPIC issued to you does not guarantee you your vote, because it is mandatory that your name should appear in the electoral roll. Once you have found out that your name is there in the electoral roll and you also possess an identification document prescribed by the Election Commission (EPIC or others), you are entitled to vote.
• Before you come to the polling booth, there are some other important aspects that you need to know as an elector and a conscientious citizen of the country.

Courtsey ECI : you can download whole document of users guide from here.