I recommend you consider this screen capture software as it works much better than the Windows Snipit tool or other such tools.Β  It includes some ability to edit and add text and leaders to screen captures.

Additionally is keeps a track of allΒ  your screen captures without your need to constantly save files.

It is free for 30 days then has a cost.Β  There is an educational license available to you for $29.95 instead of $49.99