Disable creation of multiple file resoltuions on media upload

All comes to child-theme functions.php
just for WordPress Things

// Remove unneeded WP image sizes
add_filter( 'intermediate_image_sizes_advanced', 'prefix_remove_default_images' );
// Remove default image sizes here. 
function prefix_remove_default_images( $sizes ) {
// do NOT remove small and medium sizes, they are used in backend Media Library!
// unset( $sizes['small']); // 150px
// unset( $sizes['medium']); // 300px
 unset( $sizes['large']); // 1024px
 unset( $sizes['medium_large']); // 768px
 return $sizes;
}

here for Enfold Sizes:

// Disable loads of Enfold & WP image sizes upon upload
// do image sizes manually, double-size with high compression for retina screens
// use Photoshop to set exact double size and quality between Q30 and Q40
add_action('init', 'remove_enfold_image_sizes');
function remove_enfold_image_sizes() {
// do NOT remove widget size, is used in backend portfolio items!
// remove_image_size('widget');
  remove_image_size('square');
  remove_image_size('featured');
  remove_image_size('featured_large');
  remove_image_size('portfolio');
  remove_image_size('portfolio_small');
  remove_image_size('gallery');
  remove_image_size('magazine');
  remove_image_size('masonry');
  remove_image_size('entry_without_sidebar');
  remove_image_size('entry_with_sidebar');
  remove_image_size('shop_thumbnail');
  remove_image_size('shop_catalog');
  remove_image_size('shop_single'); 
  remove_image_size('shop_gallery_thumbnail');
}

This is better to be done before making Content.
If you will make it later – you had to use some plugins like force regenerate thumbnails

PS : comment out the image sizes you like to hold on your installation

Use the plugin https://de.wordpress.org/plugins/simple-image-sizes/

It is useful for cropping, for adding own image sizes – and for avoiding unneeded images sizes:
for this simply that the image sizes to 0 height and 0 width, that you do not need (works not for existing but for new uploads).