The Amazon States Language used in Step Functions allows invocation of some AWS services directly within its state definitions. The services you can use directly from Step Functions include:

Task execution—with synchronous or asynchronous execution models (wait vs. callback):

Invoking Lambda functions

Running AWS Batch jobs

Running a task in Amazon Elastic Container Service (ECS)

Databases:

Inserting or fetching an item from Amazon DynamoDB

Messages and notifications:

Publishing a topic in Amazon SNS

Sending a message in Amazon SQS

Invoke another Step Functions workflow

It is also possible to integrate a Step Function with any service, AWS or non-AWS, by implementing your own connector inside an AWS Lambda function.

https://www.serverless.com/guides/aws-step-functions