AWS Transfer for SFTP
User Guide

Amazon S3 Requirements

AWS Transfer for SFTP accesses your Amazon S3 bucket to service your users' transfer requests, so you need to provide a bucket when setting up your SFTP server. You can use an existing bucket, or you can create a new one. When you set up your users, you assign them each an IAM role. This role determines the level of access that they have to your S3 bucket.

For information on creating a new bucket, see How Do I Create an S3 Bucket? in the Amazon Simple Storage Service Console User Guide.