Open-source licenses are legal agreements that allow software to be freely used, modified, and shared. These licenses ensure that the source code is accessible to anyone, promoting collaboration and innovation. Popular examples of open-source licenses include the GNU General Public License and the MIT License, each with its own rules about how the software can be used and distributed. By using open-source licenses, developers can protect their rights while encouraging community contributions. This approach fosters a diverse ecosystem of software projects, enabling users to benefit from improvements made by others. Open-source software is often seen in projects like Linux and Apache, which have gained widespread adoption.