Inserting snippets of HTML code into webpage document

If you need assistance and guidance about adding code to DIVI theme, it’s best to contact the DIVI theme support team directly. Here’s the link: https://www.elegantthemes.com/contact/

There are two way you can achive this.

1. Easy way- Use codde sninpets plugin like https://www.ads-software.com/plugins/head-footer-code/

Try this only and only if you are familiar with theme development
2. Create a child theme and make changes in header template.

I am trying to add an SSL TrustLogo to the landing page (and eventually other pages) of our website.

Keep in mind that if you add the code to the header/header.php template, then that code (and therefore the TrustLogo) will run on every page on the website.