You can use QuickTime; got to File/ New Screen Recording, you can capture the whole screen or frame a portion of your screen. For sound as well you have to fiddle with the settings, saves as a mov file
A couple of commercial products: Roxio has screen capture as part of the tools, I find it a bit clunky / WinEx HD Video Converter for Mac also has a tool for screen capture saves as mp4 file with other options, sound is easier just go to settings/Audio Device/System Sound. I use this it works fine