Bulk import reviews to Voxel:

1. Download plugins

Download WP all import plugin [Free version]

Download Voxel Reviews Add-on for WP All Import

2. Install and activate both in WP Admin ➝ Plugins ➝ Add new plugin

3. Go to WP Admin ➝ All import ➝ New import and upload your file

4. Select [Your post type] Reviews in the dropdown

5. In step 3 the available review fields for that post type are shown. Drag and drop the data from the file you uploaded to these fields

6. Run import