Who can use Winlink?

Who can benefit from using Winlink, and what are the requirements or qualifications for accessing its services? Is it open to individuals, organizations, or both? Are there any specific industries or use cases where Winlink is particularly advantageous? Is there a registration process or fees involved in becoming a user? Additionally, are there any restrictions or limitations on who can use Winlink or the types of transactions that can be conducted on the platform?