We recommend using the WP All Import Pro plugin to import job postings from a CSV file or Excel file. The plugin has been tested by the WP Job Manager plugin developer and a guide has been created on how to import your listings.
Follow the steps outlined at the following URL: https://wpjobmanager.com/document/tutorial-importing-job-listings-wp-import-pro/
If you have any issues with the WP All Import Pro Plugin, please contact their support team for help.