You have a variety of options for using Microsoft software licenses on AWS Cloud.
You can either continue with your current licenses or purchase integrated licenses in your new AWS environment. By purchasing Amazon Elastic Compute Cloud (Amazon EC2) or Amazon Relational Database Service (Amazon RDS) whereby licenses are included, you will receive new, fully compatible Windows Server and SQL Server licenses from AWS.
Your existing licenses can be used on AWS with Amazon EC2 dedicated instances, Amazon EC2 dedicated instances or EC2 instances with default tenancy using Microsoft License Mobility through Software Assurance (SA). Whether you want to purchase new Microsoft licenses or use existing ones, rest assured that AWS is running your Microsoft software safely and securely.
Read more about Workloads in AWS here