Adding an endpoint to your Lambda function :-

Open the Functions page of the Lambda console.

Choose a function.

Under Function overview, choose Add trigger.

Select API Gateway.

Choose Create an API or Use an existing API.

New API: For API type, choose HTTP API. For more information, see API types.

Existing API: Select the API from the dropdown menu or enter the API ID (for example, r3pmxmplak).

For Security, choose Open.

Choose Add.

https://docs.aws.amazon.com/lambda/latest/dg/services-apigateway.html#apigateway-add