Invoking sysprep (Generalising a Windows install) on AWS EC2

1. From the Windows Start menu:
   For Windows Server 2008 through Windows Server 2012 R2, open EC2ConfigService Settings, and then choose the Image tab.
   For Windows Server 2016 or later, open EC2 Launch Settings.
2. For Administrator Password, choose Random.
3. Choose Shutdown with Sysprep.
4. Choose Yes.
   Note: You must retrieve the new password from the EC2 console at the next service start.

Source: https://aws.amazon.com/premiumsupport/knowledge-center/sysprep-create-install-ec2-windows-amis/