If you want to add the custom dropdown list in the billing section of the WooCommerce checkout page, then here is the solution.
add_filter( 'woocommerce_checkout_fields', 'ts_billing_contact_checkout' );
 
function ts_billing_contact_checkout( $fields ) {
   $fields['billing']['billing_contact'] = array(
      'label' => 'Contact person from our company?',
      'required' => true,
      'class' => array( 'form-row-wide' ),
      'priority' => 28,
      'type'  => 'select',
      'options'  	=> array( // options for <select> or <input type="radio" />
	      ''    		=> 'Please select contact person', // empty values means that field is not selected
		            	'ingen_kontakt_person'	=> 'Manager', // 'value'=>'Name'
			                          'Regine'	=> 'Sales Team',
			                         'mei_mei'	=> 'Support Team'
		)  
   );
   return $fields;
}
Output
The below scenario shows that the custom dropdown list has been added to the WooCommerce checkout page.

Similar to the above feature, you can also create a text field in WooCommerce checkout page within the billing section to capture valuable customer feedback about their in-store experience.
 
													 
								
