You must have seen how many websites convert all URLs and email addresses into clickable links without you having to add any HTML code. The system automatically detects URLs and email addresses in the content and converts them into links.
If you have a WordPress website that includes lots of raw URLs and emails that you want to make clickable, it is fairly easy to do so. Add the following snippet to the functions.php file of your WordPress theme to convert all URLs and email addresses into clickable links in the main content of articles and their excerpts.
add_filter('the_content', 'make_clickable'); add_filter('the_excerpt', 'make_clickable');
Source: WP Snipp