Intro to Keynote for iCloud
Keynote for iCloud is a web app for creating and editing presentations on a Mac or Windows computer (using a supported browser). Presentations you create in Keynote for iCloud are automatically available in the Keynote app on any Mac, iPhone, or iPad that’s signed in with the same Apple ID.
This integration across devices works in both directions. You can create or edit a Keynote presentation anywhere—on a computer, iPhone, iPad, or on the web—and the changes show up everywhere. You can also share a link to a presentation with others, then edit the presentation together in real time.
After you sign in to iCloud.com (using your Apple ID) and click Keynote, you see the presentation manager. From here you can create, open, and share presentations, and more.
For more information about keeping your Keynote presentations up to date across all computers and devices, see Sync a Keynote presentation across devices.