How to take a screenshot in Mac
Sometimes it would be best for you to send us a screenshot so we can better assist you if you need assistance. Sending a screenshot should give us a better understanding of the problem you're facing.
First of all, please ensure that all the relevant windows are visible on screen. This will include the issue you'd like to highlight to us as well as any other window that may be useful for us to further assist you.
In general, what we'd suggest is that you show the Network settings as well as the problem or error message you're facing.
Once all visible windows are on screen, simply press the following keys on your keyboard to capture the entire screen:
Press ⌘Command + ⇧Shift + 3. Note that if your sound is on, your Mac should make a camera shutter sound.
Once the screenshot has been taken, you will be able to find the screenshot on the desktop. It should be saved with the filename "screenshot" and also include the time and date of when the screenshot was taken.