The OS will bring back the original Start menu and will include Windows Hello, Microsoft Passport and Windows Defender for anti-malware protection.
Optimised for both keyboard and touch, the Windows 10 upgrade is designed to be compatible with Windows devices and applications.
It will feature personal digital assistant Cortana, which learns individual preferences to provide relevant recommendations.
With Cortana integrated, Microsoft Edge – the new browser bringing built-in inking, sharing and reading view – offers results and content based on individual interests and preferences.
In addition to the Office 2016 full featured desktop suite, new Universal Windows applications for Word, Excel, PowerPoint, and Outlook will be introduced.
Windows Hello greets users by name and lets them log in to their PC without a password, but with biometric authentication.
“Windows 10 is a new generation of Windows designed to empower you to do great things,” said Terry Myerson, Executive Vice President, Microsoft. “Windows 10 starts to deliver on our vision of more personal computing, defined by trust in how we protect and respect your personal information, mobility of the experience across your devices, and natural interactions with your Windows devices, including speech, touch, ink and holograms.”