repmgr can be installed from binary packages provided by your operating system's packaging system, or from source.
In general we recommend using binary packages, unless unavailable for your operating system.
Source installs are mainly useful if you want to keep track of the very latest repmgr development and contribute to development. They're also the only option if there are no packages for your operating system yet.
Before installing repmgr make sure you satisfy the installation requirements.