The console app in macOS is a system-wide viewer for debug messages and log files. You can use it to detect errors in applications or just to get an idea of what's going on in your system.
Most of this app is not intended for the average user, as it is intended for developers who have a better understanding of the macOS operating system. Warnings and errors are very common during normal use of your computer. So do not worry if you see many of them here.
Reading the Console
You can launch the Console app from within Spotlight by pressing Command + Space and looking for it or from the Utilities folder in your Applications directory. (Open the Finder and select Applications to find it.)
The first thing you see is the console itself. This logs all messages that are generated by processes running on your system Services are sent. It's updated very quickly, so you'll have to sort something if you want to understand it.
At the top of the toolbar, there is a button labeled "Now" that automatically rolls down the window as new messages arrive. This can be useful if you are trying to debug in real time.
You can also view only bugs and errors that filter out anything without a red or yellow dot and display only the important things you might want to see.
There is also a search bar here which provides the additional functionality to search for various parameters. Just type in something, press Enter, and change the parameter from the Any drop-down list:
This option allows you to restrict the console to display only messages that are relevant to your problem.
Another view is the Activities panel, where console messages are sorted by the activity to which they are attached:
These are hierarchically ordered, so you must click the white plus sign (+) next to each to expand it.
The Log Viewer
Your system's logs work like more detailed, persistent console messages. You can find them under "Reports" in the sidebar.
The logs are divided into several categories, and most user-level applications have their logs in "~ / Library / Logs", separated by the application. Lower-level processes can be placed in / Library / Logs or / var / log. These are also available on the hard disk. So you can navigate to these folders to copy the file yourself if you want to send it to another person
There are also the categories "System Reports" and "User Reports" which contain logs for system processes and user reports. Apps are summarized.