What is a buffer solution? How to make a buffer solution?

Buffer solution is a system that minimises the change in pH when a small amount of acid or base is added. There are two types of buffer solutions- alkaline buffer solution and acidic buffer solution. The pH of alkaline buffer solution is always greater than 7, whereas the pH of acidic buffer solution is always smaller than 7.In order to make alkaline buffer solution, weak base and its salt (chloride) must be mixed together, for example, ammonia and ammonium chloride. To prepare acidic buffer solution, weak acid and its salt must be mixed. For example, ethanoic acid and sodium ethanoate.