In the Emailify export panel, select the Mailgun option from the dropdown list, then pasting in your Mailgun domain and a valid Mailgun private API key from your Mailgun account.

When you’re ready, click the Upload To Mailgun button to start exporting the emails you’ve selected from Figma to HTML, and have them automatically be uploaded to your Mailgun account, which can be viewed by logging into your Mailgun dashboard, clicking the Sending menu link, then clicking on the Templates link.