|| I want to add listings that does not have URLs. Is this possible?
|| Yes. When adding a listing from the control panel, just leave the URL field blank.
To be able to accept listings from your 'Add URL' form without requiring a URL, go to the Turbo Seek Control Panel >> Settings & Options >> General Configuration
Then look for a setting reading: 'Check that a URL is present when submitting a new listing:' - Set it to 'No'.