In WordPress, click on "Plugins":
Search "iframe". Select iframe by webvitaly:
Install this plugin. Once done, go to your page and add in a "Shortcode" element:
Here's copy and paste the code that can be found in the "Integrate" tab under "Embedded your flow":
Specifying the width and height within this is recommended, as WordPress has many conflicting features that may override this. The effects of how WordPress turns up will be affected by the container of your WordPress block itself.