In the search form, you can add a text field with certain CSS class.
Then you can customize the custom search page by editing CustomSearch.aspx file the under folder C:\Program Files\Laserfiche\WebLink\WebLink\Web Files, and modify the element with this certain CSS class.
The text field may not appear on form load so an example script is like:
<script type="application/javascript">
const interval = setInterval(() => {
const el = document.querySelector('.target-element');
if (el) {
const link = document.createElement('a');
link.href = 'https://example.com';
link.textContent = 'More info';
el.insertAdjacentElement('afterend', link);
clearInterval(interval); // stop checking
}
}, 500); // check every 500ms
</script>