Data Migration with CSFLE enabled

We are introducing CSFLE in our applications. We are currently on version 4.0 and plan to move to version 4.2 (standalone/replica-set) for taking the advantage of CSFLE feature.
This question is on data migration. The data is currently not encrypted. How do we migrate the data - with CSFLE enabled - so that the data is migrated live and is encrypted based on the json encryption schemas provided?
Is there a tool available? How do we enable CSFLE on the destination mongodb instance and configure the json schemas?
Is there any live migration service available? Need urgent guidance on this.

Thanks,
Anu