Harness streamlines AWS Lambda deployments by using a Harness Delegate installed within an AWS VPC, which connects to AWS services such as S3 buckets and Lambda functions. This setup requires configuring specific IAM roles and policies, including AWSLambdaFullAccess and AmazonS3ReadOnlyAccess. The deployment process involves defining application details within Harness, such as services, target environments, and workflows, with AWS Lambda set as the deployment type. Users can enhance their deployment pipelines with additional steps and monitor their production services using AWS CloudWatch. Harness offers a user-friendly interface for managing serverless functions, allowing for efficient software development and scalability.