Mongos are routing services for MongoDB shard configurations that process queries from the application layer and determine the location of data in a sharded cluster. To manage Mongos servers, users can easily add or remove them using Cloud Manager's deployment settings. Adding a new Mongos involves increasing the number of processes, choosing a port range, and confirming the host and other details. Removing a Mongos requires shutting down the process, reviewing changes, and confirming the reduction in Mongos processes and correct server configuration.