After installing, you can try it out for 180 days. After 180 days you and your system will run into troubles for sure. But the good news is: You can extend the period to another 180 days up to 3 years.
Extending the Trial Period
First, take a look at your desktop. You should see the countdown in the corner down right.
Or start PowerShell and run slmgr.
-dlvPay attention to the Timebased activation expiration and the Remaining Windows rearm count. You can rearm the period 6 times. (180 days * 6 = 3 years). When the period comes to an end, run slmgr -rearm to extend it by another 180 days. 1
-rearmNext restart your computer. 1
Restart-ComputerOnce restarted, open PowerShell and check your settings. 1
-dliImportant Note The evaluation version may not be used for commercial purposes. Have fun playing with the Windows Server 2016 Evaluation Version! By the way: You can do the same with Windows 10711. But the Windows 10/11 Evaluation Version can be used only for 180 days in total.