On what expenses a real estate company can take input

well if you read out sec 17(5) of CGST Act, no GST credit on construction works , but it practical scenario builder take credit and dept allows this .

your client is eligible to take credit of all of above if none of conditions mentioned below satisfied.
(1) the construction building is not single residential house
(2) the project is fall not pradhan mantri yojana or housing for all scheme .
(3) the building is sold before obtaining completion certificate..

if your client not eligible to book ITC ask him to charge from customer