How to show jquery popup only in one page or once?

The first thing you need to do is add display:none; to your CSS for both #thover & #tpopup so they are hidden by default.

Next you will want to use JS to find the URL of the page you are on and store this in a variable you can test against to determine if the pop-up should show.

Add the following to the jQuery function:

const pageURL = window.location.href;

Wrap everything else you already have in a conditional that checks if the page is Home:

if (pageURL === 'http://www33.ecoar.com.br/'){
...
}

Inside the conditional, add the following line of jQuery to show the pop-up when true:

jQuery("#tpopup, #thover").show();

The new completed JS for ‘popup.js’ will be:

   jQuery(document).ready(function () {
    const pageURL = window.location.href;
        if (pageURL === 'http://www33.ecoar.com.br/') {
            jQuery("#tpopup, #thover").show();
            jQuery("#thover").click(function () {
                jQuery(this).fadeOut();
                jQuery("#tpopup").fadeOut();
            });
            jQuery("#tclose").click(function () {
                jQuery("#thover").fadeOut();
                jQuery("#tpopup").fadeOut();
            });
        }
    });