What is the term for software that anyone can use or modify for free?

The term for software that anyone can use or modify for free is open-source software. This type of software is characterized by its license, which allows users to access the source code, enabling them to inspect, enhance, and distribute modifications. This fosters collaboration and transparency among developers and users alike, often resulting in more robust and secure applications.

Open-source software is distinct from commercial and proprietary software, which are typically sold and come with restrictions that prevent users from modifying the source code. Subscription software usually requires payment for access over a specific period but does not inherently allow for modification or open access to its source code. In contrast, open-source software embodies principles of community development and innovation by encouraging users to contribute to its improvement and adaptation.