Ttdfjt

I have a telephone number which is given in Default address..by using this telephone number i need to get Customer Full data.Data like customer id, customer full name..etc

Let us $telephone_number is value of current customer's telephone number than you can use $customer and get your data like as:-

$customer->load($telephone_number,'telephone_number');
$customer->getData();

As you have a rest tag , I assume you want to get it via REST API.

You can construct a GET request to <yoursite.com>/rest/<store_code>/V1/customers/search with the following parameters:

searchCriteria[filterGroups][0][filters][0][field]:
addresses[telephone]

searchCriteria[filterGroups][0][filters][0][value] : 123456789

searchCriteria[filterGroups][0][filters][0][conditionType]: eq

Of course, you've to add admin token on header or you'll likely to get permission denied error.

Reference

Please use the below code in test.php and run the same in the root folder.

<?php 

use MagentoFrameworkAppBootstrap; 
 include('app/bootstrap.php'); 
 $bootstrap = Bootstrap::create(BP, $_SERVER);
 $objectManager = $bootstrap->getObjectManager();
 $url = MagentoFrameworkAppObjectManager::getInstance();
 $storeManager = $url->get('MagentoStoreModelStoreManagerInterface');
 $state = $objectManager->get('MagentoFrameworkAppState'); 
 $state->setAreaCode('frontend');
 $websiteId = $storeManager->getWebsite()->getWebsiteId();
 // Get Store ID
 $store = $storeManager->getStore();
 $storeId = $store->getStoreId();
 $customerFactory = $objectManager->get('MagentoCustomerModelCustomerFactory'); 
 $customer=$customerFactory->create();
 $customer->setWebsiteId($websiteId);
 //$customer->loadByEmail('roni_cost@example.com');// load customer by email address
 //echo $customer->getEntityId();
 // $customer->load('1');// load customer by using ID
 //$data= $customer->getData();

 $objectManager = MagentoFrameworkAppObjectManager::getInstance(); // Instance of object manager
 $resource = $objectManager->get('MagentoFrameworkAppResourceConnection');
 $connection = $resource->getConnection();
 $tableName = $resource->getTableName('customer_address_entity'); 
 $sql = "SELECT entity_id FROM `customer_address_entity` WHERE `telephone`='987456123' ";
 $result = $connection->fetchAll($sql);
 $myCustomerId='';
 foreach($result as $key => $value)
 
 $myCustomerId = $value['entity_id'];
 
 $customer->load($myCustomerId);
 echo "<pre>";
 $data= $customer->getData();
 print_r($data);

 echo 'Lastname=='.$data['lastname']."</br>";
 echo 'DOB=='.$data['dob'];

 ?>

Screenshot: http://prntscr.com/fss6ql