Cloning documents is not permitted in MongoDB Compass Readonly Edition.
You can insert new documents by cloning the schema and values of an existing document in a collection.
Select the appropriate tab based on whether you are viewing your documents in List, JSON, or Table view:
When you click the Clone button, Compass opens the document insertion dialog with the same schema and values as the cloned document. You can edit any of these fields and values before you insert the new document. To learn more about inserting documents, see Insert Documents.