The most versatile approach is arguably the tool BgInfo from Sysinternals/Microsoft, which allows you to display a broad range of information about the system as the desktop wallpaper. It does require deploying and configuring bginfo.exe on the remote system(s), though, which is not always possible or allowed.
If you want just basic information like the hostname displayed on the "This PC" icon, you can accomplish that with a simple registry hack. In the key HKCR\CLSID\{20D04FE0-3AEA-1069-A2D8-08002B30309D} edit the REG_EXPAND_SZ value LocalizedString and replace the DLL reference with the string you want displayed, for instance %USERNAME% on %COMPUTERNAME%. Because the value is an expandable string (REG_EXPAND_SZ), environment variables in it will be expanded to their actual value.
Note, however, that with modern versions the registry key is owned by the TrustedInstaller principal, so you need to take ownership and grant yourself write permission before you can make that change.
