When you click on an object, Prezi's Transformation Zebra appears. It lets you move (center of the zebra), size and scale (shaded inner ring or the "+" "-" buttons of the zebra), and rotate objects of any kind (outer ring of the zebra). Clicking on the "pencil" button will initiate Edit mode of the selected object.
The Right Click Menu (Ctrl+click on Macs with default setup)
Click your right mouse button after the Zebra appears to access additional editing options. These actions are performed on the selected objects:
Bring to Front: bring the selection to the front. All objects that the selection swapped places with will be faded.
Bring Forward: bring the selection one step forward. The object that the selection swapped places with will be faded.
Send back: send the selection behind all other objects.
Send Backward: send the selection one step backward. The object that the selection swapped places with will be faded.
Cut: the selection will be cut and placed to the computer's clipboard. Results the same as the keyboard shortcut: Ctrl+x. (Cmd+x on Macs)
Copy: the selection will be copied to your computer's clipboard. Results the same as the keyboard shortcut Ctrl+c. (Cmd+c on Macs)
Paste: pastes copied or cut selections from your computer's clipboard to your prezi. Results the same as the keyboard shortcut: Ctrl+v. (Cmd+v on Macs)
Delete: Deletes the selection. Deletion of an object in Prezi can be undone by hitting the undo button of the center top menu or by the keyboard shortcut Ctrl+z (Cmd+z on Macs)