What kind of contract should i use?

[Alex Pinto]

I currently own a property with 2 units and an unfinished basement. I want to fix it and rent it out. I want to let my friend in on the deal by letting him provide his credit for the loan to fix it up. Afterward, we would let the rent pay off the loan and then split 50/50 of the profit of the rent. 

I want to start getting into the habit of having everything in writing. What would be the best form of contract to create and how will I do it?