Legal question about establishing partnership.

[Nolan Gottlieb]

I'm about to buy a deal that I've got UC. There are three of us in a unofficial partnership working together. One guy is finding deals and developing relationships, one guy is our contractor, and the last guy is our capital. What do we need to do in order to establishes how everyone gets paid once a deal sells? Do we need an LLC which establishes all three of us as part owners or should all three of us be on the title even though only one is putting up cash to buy the deal? How do folks normally establish how a payout will occur with investors? Example...an investor has agreed to loan $100K with 12% interest...surely that isn't done on a handshake deal. Is there a legal document that establishes stuff like this?