In some states like New York, a real estate attorney needs to draft a home purchase contract. In other states like California, real estate agents prepare purchase contracts using preprinted contracts that were created by attorneys.
The preprinted contracts have blanks for agents to fill in the price and terms of the offer. Real estate agents can also prepare addenda to the contract as long as they are not complicated and don't require legal expertise. If a legal document, like a release of claim or liability is to be a part of the contract, it needs to be drafted by an attorney.