How to remove class=”wp-block-heading” from Heading tags?

you can remove the class=”wp-block-heading” attribute from your heading tags by modifying your theme’s functions.php file or by using a plugin.

Option: Modify functions.php

Go to Appearance > Theme Editor in your WordPress dashboard.
Click on the functions.php file on the right-hand side.
Add the following code at the end of the file:

function remove_block_css(){
    wp_dequeue_style( 'wp-block-library' );
}
add_action( 'wp_enqueue_scripts', 'remove_block_css', 100 );

Click on the “Update File” button to save your changes.
Option 2: Use a plugin

Install and activate the “Disable Gutenberg Blocks” plugin from the WordPress plugin repository.
Go to Settings > Disable Gutenberg Blocks in your WordPress dashboard.
Select the “Disable all Gutenberg blocks” option and save your changes.
Both of these options will remove the class=”wp-block-heading” attribute from your heading tags in WordPress. However, keep in mind that removing this class may affect the styling of your headings, so you may want to add alternative styles to ensure that your headings still look the way you want them to.