You can. From this AC article:
How to take a screenshot on the Samsung Galaxy Note 4 | Android Central
If you want to take a screenshot on your Galaxy Note 4 and then annotate or edit it after the fact, the easiest way to do so is using the S Pen and the "Screen Write" option from the Air Command menu.
1. Undock the S Pen from your Galaxy Note 4. (If the Air Command menu wheel doesn't immediately appear, hover over the screen and press the button on your S Pen.)
2. Using the S Pen, select "Screen Write" from the Air Command menu, as in the photo above.
3. Your Galaxy Note 4 will capture an image of whatever's on-screen, allowing you to draw or write on top of it using the S Pen.