Custom Fields allow you to extend your WordPress site’s page content offerings by allowing you to add embedded code.
Instructions
If the Custom Fields option isn’t showing on your Edit Page / Edit Post Screen, click SCREEN OPTIONS in the upper right corner. Ensure “Custom Fields” is checked.
Begin by entering a name for your custom field. In this example, we named the custom field “code.”
In the VALUE box, paste your embed code or other text. Click ADD CUSTOM FIELD to save this data.
Enter the shortcode for the custom field as shown in the screenshot below to display its content on your newly published or updated page.