Is this a partner in your LLC? Or you have an LLC already and are looking to create JV agreements? If you are creating an LLC with a partner, you are talking about the Operating Agreement. You can find many samples online, through the paid legal sites (like LegalZoom, etc.), or through an attorney that is in that space. Keep in mind that the OA is State-specific.
If you are trying to create a JV agreement, that is far more fluid depending on what you actually do in real estate, what your JV is to do, etc. That one would be best to find samples online (they are not as clear or nice as the OA) or go to an attorney for it.
Kind regards,
Bryan