So, in this post it is explained how to supposedly enable shortcodes for custom fields in Wordpress. (Shortcodes are not enabled for custom fields by default.)

What I dont understand is where to place this code:

<?php echo do_shortcode(get_post_meta(get_the_ID(), 'name', true)); ?>

I understand I have to paste the name of my custom field into the 'name' parameter, but where do I need to place this line of code?

I suppose in the functions.php of the template? I am unsure where though in that file. I don't want to break anything of my template.

Any suggestions are appreciated.