There's debt and there's equity. Loan docs are usually a deed, promissory note, deed of trust, lender's instructions to the title company, and attorney letter of non-representation. If you ask the title company to draw docs, the attorney doesn't work for you (borrower) or lender, but the title company. When I draft docs, it is always for the lender unless specifically asked otherwise. Costs vary, but $500-800, depending on location and volume.
Equity is a whole other beast. Capital partner is on the hook for anything that happens on the jobsite. Someone gets hurt, they are named in the suit. Besides that, now you have to figure out how to structure. JV, LLC, etc. See an attorney.