Install Let's Encrypt SSL via SSH

I need assistance in installing an SSL certificate from Let's Encrypt on my mail server, accessible at mail.domain.com. The server is running on a Linux operating system, but I'm unsure of the specific distribution. The installation needs to be performed via SSH.

Key Requirements:
- Install Let's Encrypt SSL certificate on mail.domain.com
- Access and configure the server via SSH
- Ensure compatibility with the Linux operating system
- Verify the successful installation and functionality of the SSL certificate

Ideal Skills and Experience:
- Proficiency in using SSH for server management
- Experience with Let's Encrypt SSL certificate installation
- Familiarity with various Linux distributions (Ubuntu, CentOS, Debian)
- Strong troubleshooting skills to handle potential issues during installation

Please reach out if you have the expertise to help secure my mail server with Let's Encrypt SSL.