You should be able to get most documents from the Okla Real Estate Commission web site, which uses the state forms. Title companies will facilitate the process, but usually, do not stock blank forms. Some Realtors may assist in the process, for a small fee. Buyer and Seller may split this. Ditto on the inspections!
I agree with Gene. Plus, you can have the title company to handle all of that paperwork for you for an extra fee (since this is an additional set of tasks). Another alternative is to hire an agent to represent you, and have that agent to write up your offer.