// Add custom text/textarea attachment field
function add_custom_text_field_to_attachment_fields_to_edit( $form_fields, $post ) {
    $text_field = get_post_meta($post->ID, 'text_field', true);
    $form_fields['text_field'] = array(
        'label' => 'Custom text field',
        'input' => 'text', // you may alos use 'textarea' field
        'value' => $text_field,
        'helps' => 'This is help text'
    );
    return $form_fields;
}
add_filter('attachment_fields_to_edit', 'add_custom_text_field_to_attachment_fields_to_edit', null, 2); 

// Save custom text/textarea attachment field
function save_custom_text_attachment_field($post, $attachment) {  
    if( isset($attachment['text_field']) ){  
        update_post_meta($post['ID'], 'text_field', sanitize_text_field( $attachment['text_field'] ) );  
    }else{
         delete_post_meta($post['ID'], 'text_field' );
    }
    return $post;  
}
add_filter('attachment_fields_to_save', 'save_custom_text_attachment_field', null, 2);


// Add custom checkbox attachment field
function add_custom_checkbox_field_to_attachment_fields_to_edit( $form_fields, $post ) {
    $checkbox_field = (bool) get_post_meta($post->ID, 'checkbox_field', true);
    $form_fields['checkbox_field'] = array(
        'label' => 'Checkbox',
        'input' => 'html',
        'html' => '<input type="checkbox" id="attachments-'.$post->ID.'-checkbox_field" name="attachments['.$post->ID.'][checkbox_field]" value="1"'.($checkbox_field ? ' checked="checked"' : '').' /> ',
        'value' => $checkbox_field,
        'helps' => ''
    );
	return $form_fields;
}
add_filter('attachment_fields_to_edit', 'add_custom_checkbox_field_to_attachment_fields_to_edit', null, 2); 

// Save custom checkbox attachment field
function save_custom_checkbox_attachment_field($post, $attachment) {  
    if( isset($attachment['checkbox_field']) ){  
        update_post_meta($post['ID'], 'checkbox_field', sanitize_text_field( $attachment['checkbox_field'] ) );  
    }else{
         delete_post_meta($post['ID'], 'checkbox_field' );
    }
    return $post;  
}
add_filter('attachment_fields_to_save', 'save_custom_checkbox_attachment_field', null, 2);