From the Dashboard, you have the ability to crawl a specific URL from the URL Inspector tab but it will also trigger a full re-crawl of your website (according to the current settings of the Crawler).
The entered a URL will be crawled in priority and it will be processed as soon as possible, if it is compatible with your configuration.
If the URL has not been crawled previously, it will be added to the extraUrls field of your configuration.
You can also do this programmatically using the Crawler API as documented here. For more info, check Crawler’s API docs.