How can the "include" function in PHP be utilized to streamline the process of including header and footer content?

To streamline the process of including header and footer content in PHP, the "include" function can be utilized. This function allows you to include external PHP files within your current PHP file, making it easier to manage and update common elements like headers and footers across multiple pages.

// Include header content
include('header.php');

// Main content of the page goes here

// Include footer content
include('footer.php');