Adding Extra Field in Term Field both on Add and Edit Form WordPress

functions.php

add_filter( 'pa_color_add_form_fields', array( $this, 'pa_attr_taxonomy_columns' ) );
add_filter( 'pa_color_edit_form_fields', array( $this, 'edit_pa_attr_taxonomy_column' ), 10 );
add_action( 'created_pa_color', array( $this, 'pa_attr_save_taxonomy_fields' ), 10, 2 );
add_action( 'edit_pa_color', array( $this, 'pa_attr_save_taxonomy_fields' ), 10, 2 );


/**
	* Add Fields
	*
	*/
	public function pa_attr_taxonomy_columns() {
	
			$terms = get_terms( $taxonomy, array(
				'hide_empty' => false,
				'parent' => 0
				) );
			
			if ( !empty( $terms ) ) {

				?>

				<div class="form-field term-related-terms-wrap">
					<label for="related_">Related  Terms</label>
					<select name="related[]" id="related_<?php echo $taxonomy; ?>" multiple="multiple" class="postform">
						<option value="">None</option>
						<?php

						foreach ($terms as $term_value) { ?>

						<option value="<?php echo $term_value->term_id; ?>"><?php echo $term_value->name; ?></option>
						<?php
					}
					?>
				</select>
			</div>
			<?php
		}
	}
	
	
public function edit_pa_attr_taxonomy_column( $term ) {
  
  		$terms = get_terms( $taxonomy, array(
  			'hide_empty' => false,
  			'parent' => 0
  			) );

  		if ( !empty( $terms ) ) {
  			?>
  			<tr class="form-field">
  				<th scope="row" valign="top"><label>Related Term</label></th>
  				<td>
  					<select name="related[]" multiple="multiple">
  						<option value="">None</option>
  						<?php 
  						foreach ($terms as $term_value) { 
  
  							$related_color_swatches = cc_get_term_meta( $term_value->term_id, 'related', true );
  							if ( empty( $related_color_swatches ) ) {
  								$related_color_swatches = array();
  							}
  							
  							?>
  							<option value="<?php echo $term_value->term_id; ?>" <?php if ( in_array( $term->term_id, $related_color_swatches ) ) {
  								echo 'selected="selected"';
  							} ?> >
  							<?php echo $term_value->name; ?>
  						</option>
  						<?php
  					}
  					?>
  				</select>
  			</td>
  		</tr>
  		<?php
  	}
  }
  
  
  /*
  * Update terms meta
  *
  */
  public function pa_attr_save_taxonomy_fields( $term_id, $tt_id = '' ) {}