Hi@vijaykumar,
You can transfer file from ec2 instance to s3 bucket using lambda function.
Follow the below steps:
import json
import boto3
from pprint import pprint
def lambda_handler(event, context):
    client = boto3.client("ec2")
    s3 = boto3.client("s3")
    status = client.describe_instance_status(IncludeAllInstances = True)
    s3.upload_file("/home/test/sample.txt","bucket_name","testbk1122/testing/")
    return {
        'statusCode': 200,
        'body' : json.dumps('Hello from lambda')
    }
Make sure your EC2 instance is  in running status.
Hope it will help.
Thank You