That URL you provided us with, is that a dummy URL or something because it does not provide any useful information, nor does it accept any interaction.
Lastly, that can be done in a single field form, where you redirect the user to the site they are going to visit, I am writing the following code without testing, some minor elements would be needed to change,
<form>
<label for="trackingCode">Tracking Code</label>
<input type="text" name="trackingCode" id="trackingCode" />
<input type="submit" value="Track" onclick="track();" />
</form>
Then you can add the following JavaScript, that will do the job,
function track() {
var trackingCodeElement = document.getElementById("trackingCode");
window.location.href = "https://app.starshipit.com/track.aspx?code=" + trackingCodeElement.value;
}
This code is prone to errors, like the
value
can be empty or so but you can check that, and in doing so you will learn some web development as well. :-)