1.) Create system.xml at vendor/module/etc/adminhtml add below code in field
2.)create color.php file at Vendor/Module/Block
class Color extends \Magento\Config\Block\System\Config\Form\Field
{
public function __construct( \Magento\Backend\Block\Template\Context $context,
array $data = []
) {
parent::__construct($context, $data);
}
protected function _getElementHtml(\Magento\Framework\Data\Form\Element\AbstractElement $element) {
$html = $element->getElementHtml();
$value = $element->getData('value');
$html .= '';
return $html;
}
}