You can chat online with sales here.
https://www.microsoft.com/en-us/p/windows-server-2019-standard-cal/dg7gmgf0dvss?activetab=pivot%3aoverviewtab
A Windows Server CAL is a license that allows user or device to access Windows Server. CALs are used to allow Users and/or Devices to access and utilize the services of that server OS.
https://www.microsoft.com/en-us/licensing/product-licensing/client-access-license
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