Embed an external webpage onto my site

I am trying to add an external webpage to my site. I first tried adding an Embed Block via URL but the website: https://offline.licensespring.com/ doesn't allow that type of connection. I reached out to LicenseSpring and they said that I can embed it directly into the backend of my website, but I can't figure out how. I tried copying/pasting the JavaScript code from here https://docs.licensespring.com/license-api/activation-deactivation/offline-activation#QO5GD into a Code Block but that didn't work.   JavaScript Code:

var myHeaders = new Headers();
myHeaders.append("Accept", "application/json");
myHeaders.append("Date", "string");
myHeaders.append("Authorization", "string");

var raw = "{\"Payload\":\"Object\"}";

var requestOptions = {
   method: 'POST',
   headers: myHeaders,
   body: raw,
   redirect: 'follow'
};

fetch("/api/v4/activate_offline", requestOptions)
   .then(response => response.text())
   .then(result => console.log(result))
   .catch(error => console.log('error', error));

with script code, you need to wrap in script tag

<script>

your script code

</script>