Previously on Google Docs and spreadsheets: you really had to be online to use them. There was a Google Drive app that let you work on this stuff in, say, your Dropbox account. But from today, you can get Google Docs and Google Sheets for iOS and work whenever you like.
I'm not a fan of Google Docs: I revise my opinion every time I see the price – it's free – yet I've found it clunky to use. And clunky to have online all the time.
This could change my mind – and I am shocked at you for making the connection that Microsoft Office for iPad just came out. Total coincidence.
As ever, by the way, do go via these links to get the apps: going straight to the App Store and searching for them by name does not find them. Ridiculous and hopefully changing soon, but true.