Support › MB Custom Table › How to export a custom table?
How can I export and import custom tables with metabox?
To export and import custom tables, simply, you can access your database with the PHPMyAdmin tool then use its options to export and import table.
Or follow this article to export/import by coding https://code.tutsplus.com/tutorials/custom-database-tables-exporting-data--wp-28796
Meta Box just helps you to create custom tables and save field values to that, there is no native feature to export/import custom tables.