My Aunt lives in Newyork (United States) she's Indian, she's been there more than a year. I just ordered her 2 iPhone 6 phones for me and my brother personal use. The main problem is that with 2 iPhone + her own personal 1 iPhone 5s she is using. Will the Customs officials in Airport clear that 2 new Sealed iPhone as duty free or she will be charged? Help me here. If she will be charged than how much PERCENTAGE EXCISE TAX shall she pay?
As mentioned earlier the limits as far as Indian immigration is concerned are well covered in the answer to this question at Travel.SE (Travelling to India from China - Limit on Customs?),
Regarding phones specifically, legally, you can carry one personal phone and that's it. Any packaged electronics (the two iPhones your aunt plans to bring in) should be declared and if they are not declared, she risks being caught.
Another place where this is well covered is Can we carry three new smart phones in hand luggage to India?
Its a risky proposition. Depending on which Airport you are landing in, customs can scan your bag before exiting the airport and any electronics inside will be visible to them.
E.g. in Mumbai, they actually scan ALL check-in bags BEFORE they reach the baggage belt and if its suspicious they mark a big "X" on with with white chalk. Thats a the flag for the customs checkpoint to stop you. They will also ask everyone to scan their hand baggage on a machine before exiting. So unless you open up the package and carry the phone on your person (not in a bag) there is a very high chance of it getting caught.
They aren't so exhaustive in Delhi though. In Delhi they follow more of a "random selection" approach and pick out people whose bags they want to scan based on where they are travelling from (they will ask you that question). I dont know why there is a difference in the process but thats the way it is.
Carrying two phones I wouldnt worry about too much but three is kind of at the point where it gets suspicious. If you end up getting caught or declare them upfront then you'll have to pay 35% customs duty.