Purchase Agreements for Fix and Flip (Columbia, SC)

Is there already a drafted offer to purchase (contract) out there that someone could share or provide guidance on where I could get a contract that I could use to lock down an agreement between myself and a seller with the intent to fix and flip a property.   

Another question; when it comes to off market investment properties are Real Estate offer to purchase contracts sufficient to get the property under contract?

Any guidance would be appreciated. 

Thank you,