How much HRA can i claim?

HRA Exemption per month:

If you are staying in (Delhi, Mumbai, Chennai or Kolkatta)

Least of the Following

1. 50% of Basic - Rs.4300/-

2. Rent Paid minus 10% of Basic - Rs.2740/-

3 HRA Received - Rs.5590/-

Exemtion available is Rs.2,740/-

If you are staying in other city

Least of the Following

1. 40% of Basic - Rs.3,440/-

2. Rent Paid minus 10% of Basic - Rs.2,740/-

3 HRA Received - Rs.5,590/-

Exemtion available is Rs.2,740/-

Regarding documents, it is completly depends on your Company policy. Few Companies accept only valid Rent Agreement, and other will ask to submit Rent paid Receipt along with Lease Agreement.