Venture capital (VC) firms provide funding to small companies or startups which are starting to get a clear idea of their revenue stream and customers.
Venture capitalists usually pool money in a VC fund and then go about investing in prospective companies and call them their portfolio companies. The investment is expected to give returns in multiples and has less risk attached compared to seed funding.
VCs usually take an equity stake, such as with preferred shares with a host of features, in exchange for its funding, but may also provide debt funding to the company.
VC funds could help a startup with broad market research, starting commercial operations including production and sales, or with expansion, product improvement or a marketing push.
VCs may or may not be active in the decision-making of the startup management and may provide guidance with their inhouse vertical knowledge. It is all to add value to their own portfolio or the investment in the startup.
Other kinds of non-public equity funding for a business are seed funding/angel investing and private equity.