What are the best practices for extracting and displaying preview text from WordPress posts in PHP?

When extracting and displaying preview text from WordPress posts in PHP, it is important to consider the length of the text, ensure it is properly formatted, and handle special characters gracefully. One common approach is to use the `get_the_excerpt()` function in WordPress to retrieve a trimmed version of the post content.

$post_id = get_the_ID();
$excerpt = get_the_excerpt($post_id);
echo wp_trim_words($excerpt, 20); // Display the first 20 words of the post excerpt