Open source is a term derived from oss which is defined as open-source software. Open-source software or you can say its code is publicly accessible to everyone under an open-source license that means that anyone can view or modify its code.

 Many open-source projects use the GitHub platform for example LINUX.

 As we all know Linux is an open-source oss and its code is available to all, many LINUX distributions are in the market.

Difference:

Although there are many factors that distinguish an open-source and closed source software but the key difference is that an oss is free and accessible to all and any person can contribute to it, report bugs 

Solve the problems or you can say that you have the whole world to solve a problem.

Oss is fast and easily accessible as compared to closed source however non-technical communities may find closed source software easy to use but most of the programmers love to work on an open-source platform.

How to contribute:

The term open source contribution may sound difficult but it isn’t if you want to contribute to an open-source you just have to find their repository it is not the rule that you always find the repository on GitHub other platforms are also there but before contribution, you must have some knowledge of Git. If you have a fair knowledge of Git then it is almost done. You just have to find the repository of the oss you will learn about repositories in Git.

After finding a repository you will see bugs or features to be done just code, test, and contribute. your contribution is then sent for verification to the author one can also create his issues in oss repository.