What steps can be taken to ensure that the PHP file handling JSON data is saved in UTF-8 encoding for proper processing?

When handling JSON data in PHP, it's important to ensure that the data is saved in UTF-8 encoding to avoid any encoding issues. To achieve this, you can use the `json_encode` function with the `JSON_UNESCAPED_UNICODE` flag to encode the data in UTF-8 without escaping Unicode characters.

// Encode JSON data in UTF-8 without escaping Unicode characters
$jsonData = json_encode($data, JSON_UNESCAPED_UNICODE);

// Save the JSON data to a file
file_put_contents('data.json', $jsonData);