1: Create the Setup File:

Create the InstallData.php file in app/code/Vendor/Module/Setup/Patch/Data with the following content:
  
<?php

namespace Vendor\Module\Setup\Patch\Data;

use Magento\Eav\Setup\EavSetup;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Framework\Setup\InstallDataInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Catalog\Model\Product;

class InstallData implements InstallDataInterface
{
    private $eavSetupFactory;

    public function __construct(EavSetupFactory $eavSetupFactory)
    {
        $this->eavSetupFactory = $eavSetupFactory;
    }

    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        /** @var EavSetup $eavSetup */
        $eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);

        $eavSetup->addAttribute(
            Product::ENTITY,
            'custom_attribute',
            [
                'type' => 'varchar',
                'label' => 'Custom Attribute',
                'input' => 'text',
                'required' => false,
                'sort_order' => 100,
                'global' => \Magento\Eav\Model\Entity\Attribute\ScopedAttributeInterface::SCOPE_GLOBAL,
                'visible' => true,
                'user_defined' => true,
                'default' => '',
                'group' => 'General',
                'backend' => '',
            ]
        );
    }
}

Customization Options

  • type: The data type of the attribute (e.g., varchar, int, text, decimal).
  • input: The input type for the attribute (e.g., text, textarea, select, multiselect, boolean, date).
  • backend: If you need to define custom backend models for processing the attribute data, specify it here.
  • source: If the attribute is a dropdown or multiselect, you can specify a source model here to provide the options.
By following these steps, you can create a custom product attribute programmatically in Magento 2.