Design patterns are a set of templates formulated over a period of time by software architects. They are best practices that software programmers can apply to their own software/application development. They provide incredible advantages by saving time and effort by reusing pre-existing solutions while improving the quality and consistency of the code. It can also help enhance communication and collaboration with other developers, facilitate the adaptation and evolution of your code, and prevent common pitfalls and errors. All in all, design patterns are a great way to streamline your programming process.
Broadly speaking there are three kinds of patterns: structural, creational, and behavioral.