Itr for report ltcg

R/all an assessee received a sum of Rs-17,00,000 as sales consideration Sales exp- 80,000 index cost of purchase- 2,64,000 Index cost of improvement Exp- 4,55,000 Exp in Building new residential house- 12,50,000 approx Please suggest- 1- Which ITR Form to Fill 2- Which Document to be req to certify exp of new house building 3- which documentation proof will be needed to prove the cost of improvement kindly Suggest