For replication - there are no changes in the replication config required at all. Each node is own thing in this regard, passing the data unencrypted to each other in the replicaset, and to clients.
To make sure the data can’t be read as it is transferred over the network you must enable mongodb’s network encryption, which is a different part of mongodb (https://docs.mongodb.com/manual/core/security-transport-encryption/). It is supported in MongoDB community, it is not just for MongoDB Inc’s and Percona’s matching enterprise like the data-at-rest encryption.