When you design training or how-to documentation for a computer-based task, how do you show learners what to look for? Do you just tell them, or do you use screenshots of some kind?
One free way to take screenshots is Microsoft's Snipping Tool. Built into Windows operating systems (find it in Windows 10 by clicking on the start button and then typing "snip"), it provides more utility than the better-known Print Screen function.
Beyond capturing your whole screen (which it can do), Snipping Tool enables you to draw a free-form area to capture, create a rectangular angle to capture, or grab an image of a specific window in a browser or application. It also has a delay option, which enables you to take pictures of tasks in progress.
When you have a snip that you like, you can use the tool's markup features to customize it. The pen function lets you draw lines and write notes, the highlighter function does what its name implies, and the eraser function enables you to remove markups gone awry.
If you have more advanced needs, another tool you might consider is Snagit. This paid application (which offers a free trial) comes with screen recording to take videos and a feature for recording scrolling screens, neither of which are possible with Snipping Tool. It also provides a suite of image-editing tools, including the abilities to blur out information, replace text, resize images, and move objects within a screen capture.