SAN FRANCISCO — Microsoft has released an iPad version of its popular Office software suite, a breakthrough heralding a new era under a CEO who promises to focus more on the devices that people are using instead of trying to protect the company’s lucrative Windows franchise.

Thursday’s unveiling of the much-anticipated iPad apps for Microsoft’s bundle of word processing, spreadsheet and presentation software comes nearly four years after Apple Inc. released the tablet computer that has contributed to a steady decline in sales of desktop and laptop machines running on the Windows operating system.

Microsoft’s decision to relent to persistent demands to make its top-selling software application available on the world’s most popular tablet comes seven weeks after the Redmond, Wash., company anointed Sayta Nadella as its CEO after being led for 13 years by Steve Ballmer.

The change in command gives Microsoft Corp. an opportunity to prove it’s a more nimble company adapting to evolution of computing instead of clinging to its old ways.

Nadella, who has been working at Microsoft for 22 years, emphasized that he felt rejuvenated since taking over as CEO.

“You see things from a fresh set of eyes and fresh perspective,” Nadella said.

The Office app for the iPad represents a major step in the right direction for Microsoft, said FBR Capital Markets analyst Daniel Ives. “They finally looked in the mirror and realized they needed to go with the crowd in terms of iPads.”

Ives said the Office app for the iPad could generate an additional $1 billion in revenue for Microsoft. The Office app will require a subscription to Microsoft’s Office 365 to create and edit documents on the device.