Hi,
Beckhoff offers a wide range of licenses depending of the function or module you are about to use.
In my case I case, I bought a CX2020 and the PLC license TC1200-0050 and PLC-HMI License TF1800-0050.
For instance Ethernet/IP, to be able to use this a license is needed to do its function.
For learning purposes Beckhoff offers a week of trial license that can be generated directly from their TWINCAT Software. As what you can see on the attached image.