You can download the JSON file of fields configuration for MLCS from the server or data center and import it into MLCS Cloud.
Go to Settings → Issues
Go to Custom fields on left side and edit MLCS Custom field type, click on 3 dots ... → configure
Go to edit options of your custom field type
Export json tree file on right side (required plugin version 6.21.0 or newer)
Go to Settings → Issues → custom fields → mlcs → ... → context and default value → edit custom field config
Go to MLCS Cloud on left side and open tab "Import / Export"
Choose json file from MLCS Server / DC and import it.