If it was a sole membership LLC, and someone wanted to give me money to get it going, would I need to have this person sign something to show where the funds came from? Would these funds be taxable?

So I understand how a Hedge Fund gets it’s fees, it just liquidates a small part of their portfolio and pay themselves, but Funds of Hedge Funds have to invest in other funds with definite lock up periods, how do they get their annual fee? Or their performance fees for that matter?
Thanks!