Set your author name and color in Keynote for iCloud
You can also change the name shown in comments, but only for presentations that aren’t being shared.
In shared presentations, you can’t change your name in Keynote for iCloud; however, if you change your iCloud account name in iCloud System Preferences (on a Mac) or in iCloud for Windows (on a Windows computer), it’s reflected in your comments and participant list in Keynote for iCloud.
Set your color
With a presentation open, click the Tools button in the toolbar, then choose Preferences.
In the Author Settings section, click a color.
The color you choose is used for your comment bubbles, and for the editing cursor and dot beside your initials in the participant list in shared presentations.
Colors used in any presentations that are currently closed are not affected by the new color choice.
Set your name for comments in presentations that aren’t shared
Open a presentation that’s not being shared, click the Tools button in the toolbar, then choose Preferences.
In the Author Settings section, type a name in the name field.
Any new and existing comments are updated to reflect the new name.
Set your name for shared presentations
To change your name as shown in your comments and in the participant list for shared presentations, you need to change your iCloud account name. By default, the iCloud account name stored in iCloud preferences of System Preferences (on a Mac) or iCloud for Windows (on a Windows computer) is used in shared presentations.
To change your iCloud account name, visit the Apple ID account page. After you sign in, click Edit to the right of your account information, then make your changes and click Done.
The name you enter appears on all your devices where you’re signed into iCloud using the same Apple ID.
Note: In shared presentations where you’re not the owner, you can set the name in the participant list only if the presentation’s access is set to “Anyone with the link” and you’re not signed in to your iCloud account; in this case, the name you enter when you join the presentation appears in the list.