To Copy and Paste or Duplicate Objects
Any object in Artboard can be copied to the system clipboard and pasted back into the drawing or other applications such as Apple Pages(TM) or Keynote(TM). Select the object(s) and choose Edit > Copy from the main menu or use the CMND-C keyboard shortcut. Choose Edit > Paste or the CMND-V keyboard shortcut to paste objects.
Within the active layer, pasted objects will be placed with a predefined offset from the original object. When the pasted object is moved, subsequent pastes will respect the new offset of the moved object. When object(s) are pasted into a new layer they will first respect the original position, while subsequent pastes will be offset.
Alternatively, hold the Option-key while clicking and dragging an object to make quick copies in Artboard.
Alternatively, use the Edit > Duplicate > Once or CMND-D keyboard shortcut to quickly make single copies of the selected object(s).
Note, multiple objects cannot be selected among different layers.
To Copy and Paste an Object In Place (With No Offset)
There are several ways to accomplish duplicating an object and pasting in place. Quick copy a single object using the Option-key shortcut. Similar to clicking and dragging an object with the Option-key to create a copy, a simple click onto an object while holding the Option-key copies and pastes it in place.
To paste an object(s) in its original position without an offset, copy the object(s) then hold the Option-key while choosing Edit > in the main menu. The command "Paste In Place" will become available (or use the Option-CMND-V keyboard shortcut).
Alternatively, choose Edit > Duplicate > Linear Duplicate… from the main menu and set the X,Y offset to 0,0 to make multiple copies pasted in place.
Additionally, the Layer > Move To command in the main menu will cut and paste the selected object(s) in place onto a new or existing layer without offset.
To Make Copies in a Circle Around a Point Using Polar Duplicate
Choose Edit > Duplicate > Polar Duplicate… from the main menu to make multiple copies of an object centered around a point. Type the X/Y coordinates of the center point, or use the "Target" button to interactively set the center point by clicking the drawing with the mouse. Check the option to fit copies into a circle automatically. Alternatively, use the manual settings to designate the number of copies and angular increments.
To Use Linear Duplicate
To duplicate an object several times choose Edit > Duplicate > Linear Duplicate… from the main menu. Type in the desired number of copies and the desired X,Y offset (using the current drawing units).