As of ACF Pro 5.6.0, this field is built-in, so this plugin should not be used.
Allows you to select an existing piece of content or enter a custom URL, set the link title, and choose whether or not the link should open in a new window/tab.
Only works with ACF version 5 and above.
Requires PHP 5.4 or above.
After saving, you can access your data as an array:
array(
[url] =>
http://site.com/page/
[title] => Page!
[target] => 0
)