You can find your Mailgun Private API key in the API Keys section of your Mailgun account’s Settings page. You can find your Mailgun Sending Domain in the Sending domains section at the bottom of your Mailgun Dashboard.
To add Mailgun to Paragon, click the ”+” button in the workflow canvas and choose Mailgun from the sidebar. Under Connect your Mailgun account, choose “Add new account for Mailgun” and enter your Mailgun Private API Key and Sending Domain.