While we don't currently have a direct integration with Leadpages, you can add a Demio Registration Form directly within the Leadpages Page Builder.
Before you embed the form directly in Leadpages, make sure you've customized the Registration Form to your preferences.
Once done, you'll need to grab the unstyled snippet of the HTML embed code for the Registration Form from your event to embed into your WordPress website.
You can find exactly how to do that here: Embed Your Registration Form
Note: When using the unstyled form, if you make any changes to your event, you should generate a new code to embed on your WordPress website.
Using an HTML Widget
Over in Leadpages, you'll want to add an HTML Widget and paste in the HTML code.
Once you hit Publish/Update, you'll find your landing page now includes the Demio Registration Form! You can also Preview changes to see how it will look before saving them.