1. Login to your WordPress admin dashboard.
2. Under the dashboard menu, hover your mouse over Posts and click on "All Posts".
3. Tickmark the top checkbox and all checkboxes will be automatically selected.
4. Now click on "Bulk Actions" and select "Move to Trash" from the drop-down menu. Then click on "Apply".
It's done. Your post is removed from Website and no longer available for public view.
For a comprehensive guide on using bulk actions in WordPress to manage posts more efficiently, visit WordPress Bulk Actions Tutorial.
To learn more about effectively managing content in WordPress, including posts and pages, check out Managing WordPress Content: Tips and Best Practices.