As a speaker, I often find myself needing to make screenshots, and annotate them with arrows or underlines. I also often use screenshots in client reports to help educate or inform the client. It is also handy to be able to add screenshots to emails, research logs, notes, and more. My favorite screenshot tool is Snagit by TechSmith (not an affiliate link).
In the above screenshot, you can see the interface. In the large part of the screen is the working surface. The screenshot can be annotated by adding arrows, boxes, text, blur (to retain privacy), and other shapes. Along the bottom is a deck of previous screenshots. And along the right side is the menu where you can choose your tools, determine how wide or narrow the lines should be, the colors, and so on.
One of the things I use it for in my personal research is to create a list from a database, such as a list of hits in a census search, and then using the screenshot tool to keep track of what I looked at and which can be eliminated. The following is an example from a search for “Renfro” in Barren County, Kentucky in the 1850 census.
There are other features that I have not used as much such as video capture, that could be used if you wanted to demonstrate using a website or something along those lines. The TechSmith website has excellent tutorials and help pages.
I find Snagit to be very easy to use, intuitive, quick, and handy. There are probably others screenshot tools out there that you enjoy. The main point here is not necessarily to use Snagit itself, but to bring attention to how useful a screenshot tool can be. I use it nearly every day, largely to create slides in my presentations.
The screenshot can enhance whatever you are working on by providing more explanation to your audience or yourself through the use of arrows, lines, boxes, text, and more.