There are multiple methods to migrate your data into an Atlas Cluster, and the best method for import depends on your source cluster configuration.
If you are migrating a live replica set, we recommend
If you are migrating data from a CSV, we recommend
If you are migrating data from a BSON backup file, we recommend
If you are migrating data from a sharded cluster, we recommend using
mongodump(if some downtime is acceptable).
To get sample commands for any of these migration options, check your Atlas cluster's Command Line Tools. These can be found by clicking the [...] button when viewing your cluster.
READ MORE: Official documentation on migration options and proper process for each of the above is here.