To delete a page, go to Settings > Page settings.
There are two levels of deleting a page. If you change the page status to deleted, the page will be completely removed from your website, not accessible from its page slug, and will be removed from search results. You'll be able to resurrect the page at a later date and the content will continue to live in your control panel.
If you click the "Delete page" button at the bottom of the screen, the page will be permanently and completely removed from both your website and control panel. Since deleted pages cannot be restored, a pop-up will appear to confirm your decision. You cannot click the "Delete page" button if the page has subpages. You will first need to move or delete all of its subpages, blog posts, and/or events.