The word flow has many shades of meaning but most involve the steady movement of something. Water can flow in a river, electricity can flow through a wire, and talk might also flow as you sit and chat with friends.
The verb flow often describes the movement of fluids, such as water or even blood, but it can also describe other things that move in a constant stream. When you get that high-paying job, money might flow into your bank account. Until then, offers for help might flow in when you need to pay your credit card bill. Flow has a noun form as well. You might watch the flow of traffic on the street.