Emacs has a built in package manager as well as several alternative external package managers! Most of the time installing a package is as simple as running "package-install" or having a "use-package" expression somewhere in the init scripts!

I personally do not use any of these package managers and instead use my systems package manager on Gentoo to manage everything. Gentoo has most of the popular projects in the ::gentoo repo under app-emacs, and packaging your own is only a few lines of bash.