You can import existing reviews data to OnVoard via CSV File. Keep in mind that reviews import will always create new reviews. There are no options to edit existing reviews via import. Reviewed product must be added to OnVoard before review can be successfully imported.
See following guides for importing reviews data.
Need import reviews from another source?
Feel free to contact us if need us to support importing reviews from another source. Do also attached CSV template for source that you need us to support.