How can cookies be used to store user information in PHP?

Cookies can be used to store user information in PHP by setting a cookie with the `setcookie()` function. This function takes parameters for the cookie name, value, expiration time, path, domain, secure flag, and httponly flag. By setting a cookie with user information, the data can be accessed and utilized across multiple pages on the website.

```php
// Set a cookie with user information
setcookie("user_id", "12345", time() + 3600, "/");
```
In this example, a cookie named "user_id" is set with the value "12345", an expiration time of 1 hour (3600 seconds), and a path of "/". This cookie can now be accessed on other pages to retrieve the user information.