Exporting Products and Variants from Craft Commerce
If you need to update a product’s variant data already in Commerce, an easy way to do this is to export the data with Variant Manager as a CSV file, open it in your spreadsheet program to make any edits and then import it with Variant Manager again back into Commerce.
To export a product’s variant data and attributes, go to the product’s entry form in Commerce and in the right-hand column on the bottom there is an “Export Product” button.

Click it, and Variant Manager will generate a CSV file of the current product’s variant data and it will download automatically to your computer.