Using the get_field();
function you can store data in a variable.
http://www.advancedcustomfields.com/resources/get_field/
So let’s say the text box value is “http://example.com/” stored in a field called ‘url’.
First, we grab this value.
$site = get_field('url');
Then replace the http:// or https://
$site = str_replace(array('http://', 'https://'), '', $site);
Then we remove the trailing slash.
$site = rtrim($site, '/');
Finally, echo the value.
echo $site;