How do frames differ from include() function in PHP?

Frames in PHP allow for the division of a webpage into multiple sections, each with its own separate HTML document. This can help in organizing and managing complex web layouts. On the other hand, the include() function in PHP is used to include and execute the content of another PHP file within the current PHP file. While frames divide the webpage physically, include() function merges the content logically.

```php
<!DOCTYPE html>
<html>
<head>
    <title>Using Frames in PHP</title>
</head>
<frameset cols="25%,75%">
    <frame src="menu.php">
    <frame src="content.php">
</frameset>
</html>
```

In the above code snippet, frames are used to divide the webpage into two sections - one for the menu and one for the content. The menu.php and content.php files will be included and displayed in their respective frames.