How can I hide the contact address from the leads pages in classic UI?

Use Page Composer to hide the contact address in the Create Lead and Edit Lead pages in the classic UI. Here's how. You can't hide the address using Application Composer.

1. Create and enter a sandbox with Page Composer as the tool.
2. Open the page you want to configure: Create Lead or Edit Lead.
3. If you're editing the Create Lead pages, you must enter a lead name.
4. Open Page Composer from the sandbox Tools menu.
5. In the Page Composer menu bar, click the Select tab.
6. Click in the whole page component (the blue border around the whole page).
7. Click Edit Component.
8. In the Component Properties window, click Children.
9. Uncheck the Contact Address element.