If you haven't installed, please install from Atlassian Marketplace here: https://marketplace.atlassian.com/apps/1221472
Once installed, open macro browser and select HTML and Iframe Embed macro (or simply type /html to open it).
Here are some example use cases:
Example 2: Embed Google Forms
First, create form in Google Forms and copy iframe code which you can find by clicking send or share button.
Open HTML & Iframe Embed in Confluence and enter the copied Iframe code in text box.
Save and don’t forget to publish it. Your Google form will be beautifully rendered in Confluence.
That’s it. Now users can fill the form without leaving Confluence. Their responses will be saved in Google Form.
For other usage examples, please check out Confluence space:
Or other usage specific guides: