In InvokeSalesforceRestApiFunction Lambda, createRecord method can be used to create records in Salesforce.

If you haven’t setup the Connected App and Amazon Variables, please check this

How to test Salesforce SOQL from AWS InvokeSalesforceRestApiFunction Lambda function in the AWS Console?

Sample Payload to create Case record:

{
  "Details": {
    "Parameters": {
      "methodName": "createRecord",
      "objectApiName": "Case",
      "Subject": "Testing from Lambda Function",
      "Description": "Sample Lambda REST API Testing",
      "Status": "New",
      "Priority": "Medium"
    }
  }
}

Test it from AWS Console.

Output: