Azure’s pro version enables to make some extra changes in 404 Error Page for your website. Here are new features for your 404 Error Page:
- Page Type: Users can now add two types of Pages in 404 Error Page- Normal Page and Blank Page
 - Page Caption: You can now add Page Caption for your 404 Page. The default caption is ‘404‘ .
 - Page Title: Azure’s pro version users now can customize Page title for 404 Page.
 - Page Content: In Azure Pro, user can add Page Content for more proper interaction and guidance for your users.
 - Button 2: You can now add second button to your 404 Error Page and redirect your user to page you want them to visit.
 - Layouts: Users now have two different layout option for their Error Page and also can change the background image of the same page.
 
To go to 404 Error Settings:
- First go to WordPress dashboard, then Appearance >> Customize >> Inner page settings >> 404 Error
 - Make changes in your page using the given options in the customizer.
 - Go to Design tab, to change your layouts, images and button colors for 404 Error Page
 - Click on the “Publish” button to save changes and publish it.
 
For more general documentation, follow this link here: 404 Error Page Customization