I tried creating preview account through my gmail login. But I am getting the url as https://dev-xxxxx.okta.com. How can I create preview account ??
Are you looking for an org on the oktapreview.com domain? At this time, all free developer orgs are created on our Production cells, which is why all new orgs will have the *.okta.com domain.
If you want a Preview org, you will need to reach out to your Okta account manager/customer success manager to get one provisioned.