For installing packages on RedHat based systems, we use rpm (Red Hat Package Manager) command.
To install a rpm package using command line on redhat based system use -i command line switch with rpm command.
rpm -i package-1.2.3.rpm
You can also use YUM or DNF package manager to install downloaded rpm file. Its benefit to resolve dependencies required for the package.
yum localinstall package-1.2.3.rpm ## CentOS, RHEL systems dnf localinstall package-1.2.3.rpm ## Fedora systems
In case if we need to remove any package use -e command line switch with the package name.
rpm -e package-1.2.3.rpm