To setup Zillow Estimate follow the below steps:
Step1: Create a page with Zillow Estimate template:
Step2: Get the API Key
The widget works based on Zillow API. Results are returned from Zillow.
Go to this URL to take you Zillow API Key – https://www.zillow.com/webservice/Registration.htm
Step3: Add the API key in Theme options > Social & Contact > Social Accounts
Step3: Go Appearance > Widgets and add the Zillow Widget to any sidebar.