Chocolatey is a command-line package manager for Windows that automates the installation, updating, and uninstallation of applications. It offers over 10,000 community-managed application packages and can be installed via Windows PowerShell with administrative rights. To install Chocolatey, users must run specific commands in PowerShell. A GUI version of Chocolatey can also be installed after the command-line version. Users can install applications through the GUI by searching for programs and selecting them for installation, or they can use the command line to install single or multiple applications by entering appropriate commands.