Simplest way of installing mono package on RHEL9.x OS

Mono is a cross-platform, open-source implementation of Microsoft’s .NET framework. You can install Mono on RHEL-based systems using the package manager, typically dnf in recent Red Hat versions.

1. Installing epel-release rpm. Replace latest-9 with latest-8 for RHEL 8.x:
   
   sudo dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
   
2. Enabling epel:
   
   sudo dnf config-manager –enable epel
   
3. Installing mono-core or mono-complete
   
   sudo yum install mono-core OR sudo yum install mono-complete
   

More details about Mono Project on its official site: https://www.mono-project.com/