We are creating here a Boolean attribute which have value YES and NO

You need to create a file at path : Magesan\Extension\Setup\Patch\Data\CustomerAttribute.php

CustomerAttribute.php Have the below code

<?php

namespace Magesan\Extension\Setup\Patch\Data;

use Magento\Framework\Setup\Patch\DataPatchInterface;
use Magento\Eav\Setup\EavSetupFactory;
use Magento\Eav\Model\Config;
use Magento\Eav\Model\Entity\Attribute\SetFactory as AttributeSetFactory;
use Magento\Customer\Model\Customer;

class CustomerAttribute implements DataPatchInterface
{
    const YESNO_ATTRIBUTE = "yesno_attribute";
    const CUSTOMER_SOURCE = 'customer_source';

    /**
     * @var EavSetupFactory
     */
    private $eavSetupFactory;

    /**
     * @var Config
     */
    private $eavConfig;

    /**
     * @var AttributeSetFactory
     */
    private $attributeSetFactory;

    /**
     * __construct
     *
     * @param EavSetupFactory $eavSetupFactory
     * @param Config $eavConfig
     * @param AttributeSetFactory $attributeSetFactory
     */
    public function __construct(
        EavSetupFactory $eavSetupFactory,
        Config $eavConfig,
        AttributeSetFactory $attributeSetFactory
    ) {
        $this->eavSetupFactory     = $eavSetupFactory;
        $this->eavConfig           = $eavConfig;
        $this->attributeSetFactory = $attributeSetFactory;
    }

    /**
     * {@inheritdoc}
     */
    public function apply()
    {
        $eavSetup = $this->eavSetupFactory->create();
        
        // For YES And No Attribute.
        if (!$eavSetup->getAttribute(Customer::ENTITY, self::YESNO_ATTRIBUTE)) {
            $this->addYesNoAttribute($eavSetup);
        }

        // For Text Attribute.
        if (!$eavSetup->getAttribute(Customer::ENTITY, self::CUSTOMER_SOURCE)) {
            $this->addCustomerSourceCustomerAttribute($eavSetup);
        }
    }

    public function addYesNoAttribute($eavSetup)
    {
        $eavSetup->addAttribute(
            Customer::ENTITY,
            self::YESNO_ATTRIBUTE,
            [
                "type"         => "int",
                "label"        => "YES NO Attribute",
                "input"        => "boolean",
                "source"       => 'Magento\Eav\Model\Entity\Attribute\Source\Boolean',
                "user_defined" => true,
                "required"     => false,
                "visible"      => true,
                "position"     => 334,
                "system"       => false,
                "backend"      => "",
                "unique"       => false,
                'default'      => 0,
                "is_used_in_grid"       => true,
                "is_searchable_in_grid" => true,
                "is_visible_in_grid"    => true,
                "is_filterable_in_grid" => true,

            ]
        );

        $customerEntity = $this->eavConfig->getEntityType("customer");
        $attributeSetId = $customerEntity->getDefaultAttributeSetId();

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

        $yesNo = $this->eavConfig
            ->getAttribute("customer", self::YESNO_ATTRIBUTE)
            ->addData([
                "used_in_forms" => [
                    "adminhtml_customer",
                    "customer_account_edit",
                ],
                "attribute_set_id"   => $attributeSetId,
                "attribute_group_id" => $attributeGroupId,
            ]);
        $yesNo->save();
    }

    public function addCustomerSourceCustomerAttribute($eavSetup)
    {
        $eavSetup->addAttribute(Customer::ENTITY, self::CUSTOMER_SOURCE, [
            'type'                  => 'varchar',
            'label'                 => 'Customer Source',
            'input'                 => 'text',
            'user_defined'          => true,
            'required'              => false,
            'visible'               => true,
            'position'              => 334,
            'system'                => false,
            'backend'               => '',
            'unique'                => false,
            'default'               => null,
            'is_used_in_grid'       => true,
            'is_searchable_in_grid' => true,
            'is_visible_in_grid'    => true,
            'is_filterable_in_grid' => true,
        ]);

        $customerEntity = $this->eavConfig->getEntityType(Customer::ENTITY);
        $attributeSetId = $customerEntity->getDefaultAttributeSetId();

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

        $customerSource = $this->eavConfig
            ->getAttribute(Customer::ENTITY, self::CUSTOMER_SOURCE)
            ->addData([
                'used_in_forms' => [
                    'adminhtml_customer',
                    'customer_account_edit',
                ],
                'attribute_set_id'   => $attributeSetId,
                'attribute_group_id' => $attributeGroupId,
            ]);

        $customerSource->save();
    }

    /**
     * {@inheritdoc}
     */
    public static function getDependencies()
    {
        return [];
    }

    /**
     * {@inheritdoc}
     */
    public function getAliases()
    {
        return [];
    }
}

Happy Coding…