Publishing & Sharing visuals using the Embed Code
First, click "Share"from the toolbar in the Editor. Next, ensure that your visual is publicly viewable. Next, click on the "Embed" button, as shown below. (Note that this does not work when you access the Share modal from your dashboard.)
The iframe code (first) is non-responsive but the HTML code (second) is! You can choose either one of these scripts and embed it on your website :)
You can see more about embedding in Wordpress here.
Please note that if you are a PRO user and embed your visual without the Piktochart watermark, after you transition to a free account, your visual will show the Piktochart watermark after you transition.