You can embed a Nutshell Form in any CMS that accepts HTML.
To embed a form, first copy your embed snippet, from the Embed form button.
Embed a form in the Wordpress Classic editor
If you're using an older version of Wordpress with their Classic editor, click the Text tab at the top right of your content, and paste the code into the area where you want your form to appear.
Embed a form in the Wordpress Block ("Gutenberg") editor
1. Add a new Custom HTML block type.
2. Paste your form code into the newly-created HTML block. Note that you won't see your form in the block editor. It will appear when you preview or publish the entire page.
Note: if your site is hosted on Wordpress.com, you will need a Business or eCommerce plan to embed Nutshell Forms. WordPress requires this for all custom Javascript.