In MongoDB, the db.collection.remove() method removes documents from a collection. You can remove all documents from a collection, remove all documents that match a condition, or limit the operation to remove just a single document.
This tutorial provides examples of remove operations using the db.collection.remove() method in the mongo shell.
Remove All Documents
To remove all documents from a collection, pass an empty query document {} to the remove() method. The remove() method does not remove the indexes.
The following example removes all documents from the inventory collection:
db.inventory.remove({})
To remove all documents from a collection, it may be more efficient to use the drop() method to drop the entire collection, including the indexes, and then recreate the collection and rebuild the indexes.