To 404 Page
Step 0 – Navigate to the Appearance section of the WordPress dashboard, then select Customize.
Step 1 – In the Customize menu, find and click on Theme Options.
Step 2 – Look for the option labeled 404 Page within the Theme Options panel.
Step 3 – Customize the content and layout of the 404 error page, which is displayed when a page is not found on the website.
Step 4 – Once have made changes, click Publish to save them.