License your Windows Server 2019 with RDS Client Access Licenses
Each user or device that accesses a licensed Windows Server requires a Windows Server Client Access Licence (CAL).
Here you get a RDS (Remote Desktop) license for either 50 Users or Devices. They are authentic Microsoft Licenses, which can be used Worldwide.

User RDS CAL License
With the User CAL License, you purchase a CAL for every user who accesses the server to use services such as file storage or printing, regardless of the number of devices they use for that access.
Device RDS CAL License
With a Device CAL License, you purchase a CAL for every device that accesses your server, regardless of the number of users who use that device to access the server.