Screencast-O-Matic is a screen-recording software used to make capturing, recording and sharing as easy as possible. Everything you need to create quality videos is available within the software and can be used for many different purposes.

Screencast-O-Matic comes as a pro subscription service - but also has a free version with the downside being some missing features.  

See these tutorial videos that cover the basics of Screencast-O-Matic:

Editing Video with Screencast-O-Matic:

Screencasting with Screencast-O-Matic:

*Note: you must be signed into your school Microsoft Office 365 accunt for the videos to play*