Magento 2 – Add Custom Price Type in Customizable Options

Here is the way to the solution :

1. Create the module

2. Declare your new product option : app/code/Vendor/Module/etc/product_options.xml

3. Add the new custom Option in Admin/Product :

• Vendor\Module\Block\Adminhtml\Catalog\Product\Edit\Tab\Options\Type\Newtype.php
• Vendor\Module\Block\Adminhtml\Catalog\Product\Edit\Tab\Options\Option.php to define the template
• create the associated .phtml files

Vendor/Module/view/adminhtml/templates/catalog/product/edit/options/type/newtype.phtml

and

Vendor/Module/view/adminhtml/templates/catalog/product/edit/options/option.phtml

4. Add the new custom Option in Frontend Catalog :

• Vendor\Module\Block\Catalog\Product\View\Options\Type\Newtype.php;
• The associated template : Vendor/Module/view/frontend/templates/catalog/product/view/options/type/newtype.phtml
• The layout definition : Vendor\Module\view\frontend\layout\catalog_product_view.xml

5. the Models for all that

• Vendor\Module\Model\Catalog\Product\Option\Type\Newtype.php
• Vendor\Module\Model\Catalog\Product\Option.php
• Vendor\Module\Model\Catalog\ResourceModel\Product\Option.php

6. Extend Ui :

• Vendor\Module\Ui\DataProvider\Catalog\Product\Form\Modifier\CustomOptions.php

Hope this help !

Create a plugin for that. Try following way:

SR/StackExchange/etc/adminhtml/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Catalog\Ui\DataProvider\Product\Form\Modifier\CustomOptions">
        <plugin name="sr_stackexchange_custom_option" type="SR\StackExchange\Plugin\Catalog\Ui\DataProvider\Product\Form\Modifier\CustomOptions" sortOrder="1"/>
    </type>
</config>

SR/StackExchange/Plugin/Catalog/Ui/DataProvider/Product/Form/Modifier/CustomOptions.php

namespace SR\StackExchange\Plugin\Catalog\Ui\DataProvider\Product\Form\Modifier;


class CustomOptions
{

    public function afterModifyMeta(
        \Magento\Catalog\Ui\DataProvider\Product\Form\Modifier\CustomOptions $subject,
        $meta
    ) {
        $meta['custom_options']['children']['options']['children']['record']['children']['container_option']['children']['container_common']['children']['custom_text'] =
        $this->getTitleFieldConfig(
            200,
            [
                'arguments' => [
                    'data' => [
                        'config' => [
                            'label' => __('Custom Text'),
                            'component' => 'Magento_Catalog/component/static-type-input',
                            'valueUpdate' => 'input',
                            'imports' => [
                                'optionId' => '${ $.provider }:${ $.parentScope }.option_id'
                            ]
                        ],
                    ],
                ],
            ]
        );
        return $meta;
    }

    /**
     * Get config for "Title" fields
     *
     * @param int $sortOrder
     * @param array $options
     * @return array
     */
    protected function getTitleFieldConfig($sortOrder, array $options = [])
    {
        return array_replace_recursive(
            [
                'arguments' => [
                    'data' => [
                        'config' => [
                            'label' => __('Custom Text'),
                            'componentType' => \Magento\Ui\Component\Form\Field::NAME,
                            'formElement' => \Magento\Ui\Component\Form\Element\Input::NAME,
                            'dataScope' => 'custom_text',
                            'dataType' => \Magento\Ui\Component\Form\Element\DataType\Text::NAME,
                            'sortOrder' => $sortOrder,
                            'validation' => [
                                'required-entry' => false
                            ],
                        ],
                    ],
                ],
            ],
            $options
        );
    }
}

Clear Magento cache.

NB: This solution only for M2.1.x. and greater.

[Update]

How to save?

-> create a column 'catalog_product_option' table same as field name. e.g: custom_text

-> clear cache.