10.13 High Sierra and earlier : Use key shortcuts (see below) or Grab.app (see here)
11.14 Mojave and after: Snapshot.app (more info here):
- Similar to Grab but after you’ve taken the snapshot it allows you to annotate/markup the screenshot, and then you can either copy and paste from there or save as a file.
- Additionally in Screenshot, it remembers the position on screen of an area screenshot so you can easily take repeated screenshots from the same portion of your screen.
Key shortcuts in all Mac OS X / MacOS versions (see here)
Shift + Cmd + 3 : captures whole screen
Shift + Cmd + 4 : starts a region screenshot, select a region of the screen
- before 10.14 Mojave, saves a .png to your desktop
- 10.14 Mojave and after – opens screenshot in the Screenshot editor app