The two government charges on buying a property, what they are paid on and why they differ.
Stamp duty is a state tax on the document that transfers a property. Registration is a fee for recording that document with the sub-registrar. Until the sale deed is stamped and registered, the transfer is not complete in law, whatever has been paid to the seller.
They are charged on the value in the agreement or on the value the state's government sets for that area, commonly called the circle rate or ready reckoner rate, depending on the state's rule. In many states it is whichever is higher, so a deal struck below the government's value is still charged on the government's value.
For that reason the figures on this site are indicative and carry a note to confirm with the sub-registrar. Use the stamp duty calculator to estimate, then ask your lawyer or the registration office for the exact amount.
Most states now take payment online through an official portal, and the receipt is attached to the deed. Do not hand cash to an agent for it. Keep the receipt with your other property papers.
This guide is general information, not legal, tax or financial advice. Rules differ between states and change over time, so confirm the details that matter to you with a qualified professional or the authority concerned before you act.