Taking a screenshot in macOS really couldn’t be simpler. What you can’t do, at least by default, is take a screenshot on delay — for those times you’d really like to complete an action (like hitting a play button, for example) before snapping the screen grab.
Though not accessible by default — aside from using Quicktime to create a screen recording video and then taking a still image from it — you can achieve what you’re looking for with a Terminal command. This command, when executed, allows you to screenshot anything with a five or 10 second delay.
To achieve what you’re looking for, just tweak the time (T15=15 seconds), the file name, and location to your liking.
Allow access to record screen
1) Click the apple icon to open the menu.
(Image credit: Tom’s Guide)
2) In the menu, select System Preferences.
(Image credit: Tom’s Guide)
3) In the System Preferences, select Security & Privacy.
(Image credit: Tom’s Guide)
4) In the left pane, scroll down to find Screen Recording.
(Image credit: Tom’s Guide)
5) In the Privacy tab, select Terminal.
(Image credit: Tom’s Guide)Run the command to record screen
1) Click the Finder icon to open a Finder window.
(Image credit: Tom’s Guide)
2) In Applications, search Terminal.
(Image credit: Tom’s Guide)
3) In the search results, select Terminal.
(Image credit: Tom’s Guide)
4) In the Terminal window, type screencapture -C -T15 Desktop/ScreenCap.png.
(Image credit: Tom’s Guide)
5) Press Enter to run the command.
Note: Minimize the Terminal window so that the screenshot does not capture it.
