Template tag?

I’m not exactly sure what you’re asking. The plugin uses a shortcode only and can be used in any post, page, widget, or template.

Full documentation: https://www.macardam.com/a-random-number/

Can you give an example of how to use it in a template.

If you’re using it anywhere in the WP editor, just use the shortcode

[arandomnumber]

If you’re using it in templates or anywhere you have to call it via php, use the code:

<?php echo do_shortcode('[arandomnumber]'); ?>