@Henry Urey Rivas,
Contracts are critical in this business. I use a four-page contract. Unfortunately, I can't share it due to how I got it. But you really need to make sure you cover your bases. Your contract should take into consideration several things:
(1) Clearly identify the property and all parties involved. This should all be in legal terms. Are you acting as an individual or a company/entity? Who technically owns the property? How do you legally identify the property? (2) What is the price you're offering, what kind of EMD are you offering, and who is going to hold that? (3) What costs are involved, and how are they going to be handled? Are you going to pay past due taxes? Is the owner going to pay closing costs? There are several real and potential costs to be considered. (4) What happens if there is a sudden loss during closing, like a fire? (5) Do you have a Due Diligence period where you get to verify the status of ownership and the property itself, and if there's a problem, do you have the opportunity to withdraw from the deal? (6) What happens if you or the seller decide to withdraw from the contract for no reason that's allowed under the terms of the contract?
These are probably most of the issues you have to address, but I'm pretty sure it's not everything. It also depends on where you're operating. What is required for your state/locality?
I recommend connecting with local investors, realtors (yes, they are a good resource), title companies, etc. to find out what they use and what they're doing.
Don't go cheep and dirty. Make sure your bases are covered.
Good luck!