Open source application software is computer software that has source code that can be modified or enhanced by anyone. The source code contains the underlying programming code that determines how the software looks and works.
Software that allows only the software owners to modify the source code is called proprietary software or closed source software. In this case, only the original authors are legally allowed to copy or modify the source code. Examples of proprietary software are Microsoft Office and Adobe Photoshop. A person who buys a copy of proprietary software is actually buying a license to use the software according to its terms, which often specify how many copies can be made and restrict access to the source code.
In contrast, open source software is released to the public with a license that allows anyone to view the source code, copy it, modify it and learn from it. Some open source licenses require that anyone sharing the source code do so without charging a fee. The goal is to promote collaboration and sharing among programmers and anyone else interested in software development. As a result, open source software is usually reliable and secure. LibreOffice is an example of open source application software.