You can access the system configuration through the Stores > Configuration > WebForms admin page.
General settings that are required to connect Zendesk Support and Magento.
The domain is your address (yourdomain.zendesk.com) within the Zendesk system.
#Agent Email Address
Your registered email address in Zendesk system.
The token that you create in the Zendesk Admin > Channels > API page.