How to modify api gateway response headers and contents

Hello.

The mapping template syntax is described in the following documentation:
Based on this, the response from Lambda can be processed by API Gateway and returned to the user as a response.
https://docs.aws.amazon.com/apigateway/latest/developerguide/models-mappings.html

I am using an image of a slightly older management console, but I think the following blog will be helpful for setting up.
https://medium.com/@nwosuonyedikachi/how-to-do-input-output-mappings-in-the-api-gateway-for-lambda-functions-on-the-aws-cloud-console-8f4304f25dc2