If you are having WiFi issues there are several things you can do to troubleshoot. Of course, there are third party programs you can buy and use for this purpose, but there is a way to check your WiFi right within the macOS.
If you are having WiFi issues or if you just want to check your WiFi settings here is what you do. Hold down the Option Key ⌥ while you click on the WiFi icon in your menubar. You will see this extended menu:
You can see more technical settings in this dropdown list. If you want to know more about what all those terms mean read this article. But, what you really want to do is select “Open Wireless Diagnostics”. You will be presented with this app window explaining what the app can do:
Just click on the “Continue” button and the app runs a diagnostic on your WiFi setup:
This can take about a minute or so. When it is done it will present you with a report:
Even if it says your WiFi setup is running as expected choose the “Continue to summary” box and hit “Continue”. You will be taken through a couple of screens where you can put in information about your WiFi equipment. You will then be presented with a window like this:
Even though the app said my WiFi was running as expected it did report a crowded WiFi channel. That means several people around me (neighbors) are using, in this case, Channel 11 for their WiFi connection. The Diagnostic app suggests restarting my Cable Modem to try to get it to connect using a different Channel with less traffic on it. After I restarted the modem and ran the Diagnostic again I got this report:
The crowded channel message is gone, the modem picked up another channel which means smoother sailing for me.
By the way, the app produces a zip file of a much more thorough WiFi diagnostic and places it on your Desktop. I looked at this, but could not make heads or tails of it. I think this would be a file you sent to Apple perhaps.
This procedure is not the end-all of diagnosing your WiFi issues, but it is a pretty handy tool and worth trying. Even if you are not having WiFi issues it would still be interesting to run it.