Cash Flow is understood as the movement of money in and out of money (ie received and spent) in a shop, business, project or financial product.
The goal of small businesses/stores is to create a positive cash flow (Positive Cash Flow), that is, how to receive more money in than spend money. This sounds easy and simple, but a lot of companies have problems with their cash flow. If the revenue is not stable, it is also difficult to pay daily expenses such as salary, electricity, water, etc.