This class  new TaxonomyEdit( $args ); use to add custom input fields under any taxonomy create and edit page. there is no limit to add custom input fields, there are 48+ different input fields you can add dynamically under taxonomy edit or create page.

For example you can add custom input field under category page (wp-admin/edit-tags.php?taxonomy=category) like follows.

You need to add following code under theme  functions.php files to work or any others plugin file.

$options = array(
        'id'		    => 'text_field',
        'title'		    => __('Text Field','text-domain'),
        'details'	    => __('Description of text field','text-domain'),
        'type'		    => 'text',
        'default'		=> 'Default Text',
        'placeholder'   => __('Text value','text-domain'),
        'id'		    => 'textarea_field',
        'title'		    => __('Textarea Field','text-domain'),
        'details'	    => __('Description of textarea field','text-domain'),
        'value'		    => __('Textarea value','text-domain'),
        'default'		=> __('Default Text Value','text-domain'),
        'type'		    => 'textarea',
        'placeholder'   => __('Textarea placeholder','text-domain'),

$args = array(
  'taxonomy'       => 'category',
    'options' 	        => $options,
$TaxonomyEdit = new TaxonomyEdit( $args );