What are the best practices for passing variables between PHP scripts using forms and methods like GET and POST?

When passing variables between PHP scripts using forms and methods like GET and POST, it is important to ensure that the data is sanitized to prevent security vulnerabilities. To pass variables using GET, you can append them to the URL as query parameters. To pass variables using POST, you can submit a form with hidden input fields containing the data.

// Passing variables using GET method
<a href="script.php?variable=value">Link</a>

// Passing variables using POST method
<form action="script.php" method="post">
    <input type="hidden" name="variable" value="value">
    <button type="submit">Submit</button>
</form>