Creating an index on a MongoDB collection is simple; just run the command CreateIndex and thats all there is to it. There are several index types available, and in a previous post, you can find the more important index types: MongoDB index types and explain(). The command is quite simple, but for MongoDB, building an [&]

https://www.percona.com/blog/2019/08/05/mongodb-impact-free-index-builds-using-detached-replicaset-nodes/