A VC firm has general partners (GPs) who own the firm and manage the money and funds. It may also (and usually does) have limited partners (LPs) who invest money in one or more funds but don't play any management role.
And, more importantly, who have no say in how their money will be invested.
You got a couple of technical replies (which are correct) but the answer what you are looking for is that they are the VC’s customers.
They pay the investment firm to invest their money, typically 2% of funds invested annually plus 20% of any realized profits.
Limited Partner. The people who invest in Venture Capital funds