How can i insert Google Adsense advertisements into my posts?

I’m trying to insert ad banners or ads in general from google adsense into my posts, the code for these ads look something like this:

<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<!-- banner -->
<ins class="adsbygoogle"
     style="display:inline-block;width:728px;height:90px"
     data-ad-client="ca-pub-020143294238784835738"
     data-ad-slot="435298745345"></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({});
</script>

It doesn’t look like normal HTML so i tried to insert it into my posts through the text editor, and it ended up showing a bunch of off placement, off centered text that didnt look anything close to an ad. How can i insert these into my posts?