pacman is Arch linux's package manager. similar to apt in debian and dnf in fedora but much more complex as several
operations depend on multiple use flags.
One can go read https://wiki.archlinux.org/title/Pacman on the arch wiki but a quick synopsis is as follows.
pacman -S packagename installs a package (must be run with root priveleges)
pacman -R package name uninstalls a package
pacman -Rs uninstalls the package and its dependancies if not used by other packages.
pacman -Ss search for a package
pacman -Syu upgrade all packages to the very latest
in addition their are a few other useful commands.
paccache -r cleans the package cache of old unneded package versions
pactree packagename lists all dependancies for a package