Technical Giants!!
Refer it!
NameTypeInformation
Google Search Engine, Every kind of developer Owns Android OS
Microsoft Every kind of developer Owns Windows OS
Adobe Many kind of developer Known for making Adobe Acrobat, Adobe Photoshop and many more professional softwares and/or applications.
Apple Hardware developer Owns IOS(Iphone OS and Ipad OS)

Learning and Education
NameTypeInformation
Wisdom Eye Offers courses for students from class 5 up to college -
Vedantu Focuses mainly on live learning and live quizez.Also offers many past videos and tests. -
Byju's Offers everything for learning. Offers everything for learning including but not limited to question-answer site, tests and exams, plenty of recorded videos for classes and lectures, and live classes!