How to send data to API Post to be used by Lambda Function

I'm trying to post my customer name using fetch, in an async function.

     async function ExecuteEC2(customer) {
        const response = await fetch(
          'https:api',
          {
            method: 'POST',
            body: {
              Customer: customer,
            },
    
            success: function (response) { 
              alert(response.status);
            },
            error: function () {
              alert("error with database");
            }
          }
        );
        
      }

The function is used in my button so that when it is clicked it triggers the API.

    <button
                className="btn btn-primary bt-btn btn-size"
                type="button"
                onClick={() => {
                  alert("Oh, hi " + customer);
                  ExecuteEC2(customer);
                }}
              >
                Configure Ansible
              </button>
              <Modal
                showModal={showModal}
                setShowModal={setShowModal}
                devices={options.AllCSRList}
                user={user}
                customer={customer}
              />

Finally, the lambda function has been set up to read and apply the API data to our EC2. However, it doesn't show up whenever I try to grab the customer data. Where and how would I amend this to push it through the post?

    import time
    import json
    import boto3
    import urllib3
    import requests
    from pprint import pprint 
    
    region = 'eu-west-2'
    instance = 'i-ec2'
    ec2 = boto3.client('ec2', region_name=region)
    
    def handler(event, context):
    
        customer_name = event['Customer']
    
        
        print(customer_name)
    
        #boto3 client
        client = boto3.client('ec2')
        ssm = boto3.client('ssm')
        # status = client.describe_instance_status(IncludeAllInstances = True)
        # pprint(status)
        
        # response = ssm.send_command(
    
        #     InstanceIds=['i-ec2'],
        #     DocumentName="AWS-RunShellScript",
        #     Parameters={'commands':[
        #     "mkdir create2.txt",
        #     ]},
                
        # )
            
        # print(response)
        
        
        return {
            'statusCode': 200,
            'body': json.dumps(customer_name)
        }

Note: I am writing my answer with respect to javascript version of lambda.
The post data is in the body property of the event object.

body = event["body"]

Also the the body is a json string and you will have to convert it to a json/dictionary.

then

customer_name = body["Customer"]

To fix this issue I had to redo my async function.

I first added the function to my API call file.

async function ExecuteEC2API({ apiName, path, user, body }) {
  // replace this with the path you have configured on your API
  let jwt = user.signInUserSession.idToken.jwtToken;
  let myInit = {
    headers: { Authorization: `${jwt}` }, // OPTIONAL
    response: true,
    queryStringParameters: body,
  };
  try {
    const response = await API.post(apiName, path, myInit);
    console.log(await response);
    return await response;
  } catch (err) {
    console.log("fetch failed", err);
  }
}

Following this, I then edited the async function in the deploypage.js to call what was needed,

  let ExecuteEC2 = async () => {
    let response = await ExecuteEC2API({
      apiName: ....,
      user: user,
      body: {
        method: "query",
        Key: Key,
        Customer: customer,
      },
    });
    console.log("EC2", response);
    await delay(5);
  };

This seemed to do the trick!