Lightshot
A great and easy program for creating screenshots
To use, press the PrintScreen key, next to F12.
After selecting the screenshot area, you can add:
You can also save to a file, and even copy (ctrl+c) directly from the program, without saving, and then paste (ctrl+v) to Whatsapp on the computer (web.whatsapp.com) or any other software which supports pasting images.
We use it a lot for questions and answers between mentors and students, and also in the development process between team members.