Business is new but growing and friends and family want to invest

[Adam Soyak]

Currently, I own some rentals, 2 SF homes, 1 two-flat, and an additional BRRRR closing next month. I have flipped 4 homes as well. These properties are all in my personal name, and will be under an umbrella policy very soon.

Friends and family are now reaching out wanting to invest witnessing the decent track record I have developed.  Amounts range from $10k-$30k each that they would be willing to invest into my future projects.  Most of my personal funds are now tied up in the rentals so using OPM is definitely attractive to keep this train moving.  

I am trying to figure out what kind of agreement to come up with that is fair for both parties.  I am open to suggestions, just not sure what is typical to start (ie interest, duration, terms, etc)  I also am not sure if I need to form some type of syndicate or other entity for this to work and be legal.  Is there any letter or promissory note that you have used in a similar situation?

Any advice would be greatly appreciated!