Create Your Own Custom 404 Page
Follow these steps to create a custom 404 page and assign it using Elementor and the WordPress Customizer:
Step 1: Create a New Page
Go to Pages: Navigate to Pages > Add New in your WordPress Dashboard.
Add a Title: Enter a name for the page, such as Custom 404 Page.
Edit with Elementor: Click the Edit with Elementor button to design your custom 404 page.

Step 2 : Assign the Page as Your 404 Page
Go to Appearance > Customize: In your WordPress Dashboard, navigate to Appearance > Customize > 404 Page.
Enable Custom Page:
Enable the option to use a custom page for your 404 error.
Select Your Custom Page:
From the dropdown menu, choose the Custom 404 Page you created.
Publish Changes:
Click Publish to save and apply your new 404 page to your website.