UpgradeData.php

<?php
/**
 * Copyright (c) 2019  Landofcoder
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

namespace Lof\CustomCustomerInfo\Setup;
use Magento\Framework\Setup\UpgradeDataInterface;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\ModuleContextInterface;
use Magento\Customer\Setup\CustomerSetupFactory;
use Magento\Customer\Model\Customer;
use Magento\Eav\Model\Entity\Attribute\Set as AttributeSet;
use Magento\Eav\Model\Entity\Attribute\SetFactory as AttributeSetFactory;


class UpgradeData implements UpgradeDataInterface {

    protected $customerSetupFactory;
    private $attributeSetFactory;

    public function __construct(
        CustomerSetupFactory $customerSetupFactory, AttributeSetFactory $attributeSetFactory
    ) {
        $this->customerSetupFactory = $customerSetupFactory;
        $this->attributeSetFactory = $attributeSetFactory;
    }


    public function upgrade( ModuleDataSetupInterface $setup, ModuleContextInterface $context ) {

        if (version_compare($context->getVersion(), '1.0.4') < 0) {

            $setup->startSetup();
            $customerSetup = $this->customerSetupFactory->create(['setup' => $setup]);

            $customerEntity = $customerSetup->getEavConfig()->getEntityType('customer');
            $attributeSetId = $customerEntity->getDefaultAttributeSetId();

            $attributeSet = $this->attributeSetFactory->create();
            $attributeGroupId = $attributeSet->getDefaultGroupId($attributeSetId);

            $customerSetup->addAttribute(\Magento\Customer\Model\Customer::ENTITY, 'customer_avatar', [
                'type' => 'text',
                'label' => 'Image',
                'input' => 'file',
                "source" => '',
                'required' => false,
                'default' => '0',
                'visible' => true,
                'user_defined' => true,
                'sort_order' => 210,
                'position' => 210,
                'system' => false,
            ]);

            $image = $customerSetup->getEavConfig()->getAttribute(Customer::ENTITY, 'customer_avatar')
                ->addData([
                    'attribute_set_id' => $attributeSetId,
                    'attribute_group_id' => $attributeGroupId,
                    'used_in_forms' => ['adminhtml_customer', 'customer_account_create', 'customer_account_edit'],
                ]);

            $image->save();
            $setup->endSetup();
        }
    }
}