FREE All in One Online Teaching Tool with A to Z Solution in 2022

Which free software is best for online teaching?
Which tool is best for online teaching?
How can we teach online with free tools?
What is the best free PDF annotator?
How can I annotate a PDF for free?
PPT Download Link: 

Free Screen Recorder
Free videos editing software
Best PDF annotation tool
PPT to Video maker
Mouse Cursor Highilight with 
Click sound effect
Camtasia Alternative software
All in one teaching videos maker
Educational video recorder