1. Create a New Report.
2. Select the Document object type.
3. Add your desired results columns.
4. Run the report.
5. Once the results are loaded, select one or more documents.
6. Click on Clean Version History in the quick actions on the right.
7. You will then be provided with the option to Delete All Versions (except for the most recent major version and its last draft) or to Delete Minor Versions (only preserving all major and current versions).
8. Click Clean.