Hi @Rakshith_79674,
The config.databases collection stores a document for each database in the cluster, i.e., the databases for which we have enabled sharding.
MongoDB Enterprise mongos> db.databases.find().pretty()
{ “_id” : “m103”, “primary” : “m103-repl-2”, “partitioned” : true }
The actionlog contains the details of operations occurring related to that same database.
MongoDB Enterprise mongos> db.actionlog.find().pretty()
{
“_id” : “m103-2019-09-25T10:56:22.065+0000-5d8b47d619f570dae0633167”,
“server” : “m103”,
“clientAddr” : “”,
“time” : ISODate(“2019-09-25T10:56:22.065Z”),
“what” : “balancer.round”,
“ns” : “”,
“details” : {
“executionTimeMillis” : 22787,
“errorOccured” : false,
“candidateChunks” : 1,
“chunksMoved” : 1
}
}
The reason that you are unable to see config.databases collection here in your config db might be that sharding hasn’t been enabled on applicationData.
As a reference, to see the details of databases and actionlog collection, you may look for these when you enable sharding on m103 in Lab: Shard a collection.
Let me know if this helps, happy learning! 
Thanks,
Muskan