Log options are found on the Server Settings tab in the Operations Center.
Debug logging should only be enabled for troubleshooting purposes. It will generate a much more detailed log to allow support personnel to troubleshoot your server. However, debug logging should NOT be switched on during normal production, since it will generate very large log files that contain excessive information that you will not need when the system runs as expected.
The Application log time zone is set to the server's time zone by default. This implies that events that are written to the application log files are recorded using the server's local time zone. If you would rather store the logs in UTC format, choose that option instead using the radio button.