I’ve tried the proposed solution on another question to get my catalog_url to link to an external site to work.
What happens instead is I get a plain http link. So I checked my ACF and yep, the link is in there as http://www.example.com. Below is the code in my template:
<?php if( get_field('catalog_url') ): ?>
<p><strong>Catalog:</strong> <a href="<?php the_field('catalog_url')?>"> <?php the_field('catalog_url') ?> </a></p>
<?php endif; ?>
The expected output (if there is a URL in the field) is:
Catalog: http://www.example.com