shortcode not working inside input field value

example code on page
<input placeholder="20" name="distance" type="text" value="[qv var=distance]" />

example code in functions.php file

function get_qv($atts)
{
    return get_query_var($atts['var']);
}

add_shortcode('qv', 'get_qv');

add_filter('query_vars', 'custom_query_vars');

but this
[qv var=distance]
is showing on the page to the end user.
I have been looking for ways to fix it.

I found this

“As such you should use your snippet to output the full value parameter (value=”xyz”), or the entire input itself.”

no idea what that means.

Any ideas?
Thanks