Snippet code to show field on pos panel

if(!function_exists('openpos_product_addition_fields'))
{
    function openpos_product_addition_fields($session_response_data){


        //custom product fields
        $session_response_data['setting']['openpos_product_addition_fields'] = array();
        $session_response_data['setting']['openpos_product_addition_fields'][] =   array(
            'code' => 'text_field',
            'type' => 'text',
            'required' => 'yes',
            'label' => 'Text Field Label',
            'placeholder' => 'Enter text field',
            'description' => ''
        );

        $session_response_data['setting']['openpos_product_addition_fields'][] =   array(
            'code' => 'checkbox',
            'type' => 'checkbox',
            'label' => 'Checkbox',
            'options' => array(
                ['value' => 'male','label' => 'Male'],
                ['value' => 'female','label' => 'Female'],
            ),
            'placeholder' => 'Checkbox Sample',
            'description' => '',
            'default' => array('male'),
        );
        $session_response_data['setting']['openpos_product_addition_fields'][] =   array(
            'code' => 'radio',
            'type' => 'radio',
            'label' => 'Radio',
            'options' => array(
                ['value' => 'radio1','label' => 'Value 1'],
                ['value' => 'radio2','label' => 'value 2'],
            ),
            'placeholder' => 'Checkbox Sample',
            'description' => '',
            'default' =>  array('radio2'),
        );
        $session_response_data['setting']['openpos_product_addition_fields'][] =   array(
            'code' => 'select',
            'type' => 'select',
            'label' => 'Select Fields',
            'options' => array(
                ['value' => 's1','label' => 'select 1'],
                ['value' => 's2','label' => 'select 2'],
            ),
            'placeholder' => 'Checkbox Sample',
            'description' => '',
            'default' => array('s2'),
        );

        return $session_response_data;
    }
}
add_filter('op_get_login_cashdrawer_data','openpos_product_addition_fields',10,1);

Code to handle data submit by add custom product form

add_action('openpos_after_add_custom_product',function($product_id,$product_data){
    $text_field = isset($product_data['text_field']) ? trim($product_data['text_field']) : '';
    $radio_field = isset($product_data['radio']) ? trim($product_data['radio']) : '';
    //implement your logic to product with custom data as you want
},10,2);