MX records, or Mail Exchange records, are a type of DNS (Domain Name System) record used to direct email messages to the correct mail servers. They specify which server should handle incoming emails for a domain, ensuring that messages reach their intended destination. Each MX record has a priority value, allowing multiple servers to be listed in order of preference. When an email is sent, the sending server queries the DNS for the MX records of the recipient's domain. The server then connects to the mail server with the highest priority to deliver the email. This system helps manage email traffic and provides redundancy in case one server is unavailable.