CentOS/RHEL machine are using epel repositories to install various packages supported for various versions. epel is basically is Extra package for Enterprise Linux hosted through fedora project. On this link we have rpm for various RHEL/CentOS version that would create repo file which then allow to install these provided packages.

Let’s take this example for CentOS8.2 Machine .. and Try to install epel package to enable epel repositories for extra packages

[root@srv19 ~]# cat /etc/redhat-release                 
CentOS Linux release 8.2.2004 (Core)                    
[root@srv19 ~]# uname -r                                
[root@srv19 ~]# lsb_release -d                          
Description:    CentOS Linux release 8.2.2004 (Core)    

For CentOS Machines we just need to install one epel RPM which has no dependencies and only need to place in repo file in /etc/yum.repos.d/ directory.

yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
Dependencies resolved.                    
Transaction Summary                       
Install  1 Package                        

Running transaction                                 
  Preparing        :                                
  Installing       : epel-release-8-8.el8.noarch    
  Running scriptlet: epel-release-8-8.el8.noarch    
  Verifying        : epel-release-8-8.el8.noarch    

After this if we try to search repolist on CentOS8 machine we would found it like this and we further could install various packages provided in epel repo