Configure Windows to automate logon – Windows Server

To use Registry Editor to turn on automatic logon, follow these steps: Click Start, and then click Run. In the Open box, type Regedit.exe, and then press Enter. Locate the HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWinlogon subkey in the registry. Double-click the DefaultUserName entry, type your user name, and then click OK.

https://learn.microsoft.com/en-us/troubleshoot/windows-server/user-profiles-and-logon/turn-on-automatic-logon