Open-source software is a project that makes source code publicly available. These projects are protected by open-source licenses which restrict how code can be used and for what purposes. Open-source software is generally free for use or modification by standard users.
Open source components enable you to quickly develop software. You don’t need to start from scratch. Rather you can find a project that already exists and build on it. Using open source components can save you a lot of dev time. However, to avoid introducing vulnerabilities into your quality codebase, you need to properly secure your open source components.