Assuming this is a real estate contract to purchase an existing home, you need the following items: the lot and block number; street address; name and address of the seller; name and address of the buyer; a brief description of the location of the house in terms of metes and bounds; information about zoning, the heating, sewer and water systems.
It should include agreed purchase price, montlhly payment, length of payments, information as to who is responsible for insurance, taxes, etc... Contract should be signed by both seller and buyer. Also, both signatures should be notorized.
Suggest google examples of land contracts. Modify to fit your situation. Take it to an attorney to look over. Or suggest having the attorney draft for you.