To copy one or more sketch entities, select the entities,
then click Edit, Copy,
or press Ctrl+C. Click in the
graphics area, then click Edit,
Paste or press Ctrl+V.
The center of the sketch entities is placed where you clicked.You can cut and paste, or copy and paste, one or more sketch entities from one sketch to another or within the same sketch.
With any sketch entity in an open sketch, you can:
Copy the sketch entity within the same document or to different documents. Hold down Ctrl while dragging the sketch entity.
To copy one or more sketch entities, select the entities,
then click Edit, Copy,
or press Ctrl+C. Click in the
graphics area, then click Edit,
Paste or press Ctrl+V.
The center of the sketch entities is placed where you clicked.
Move a sketch entity within the same sketch. Hold down Shift while dragging the sketch entity.
Move a sketch entity between different documents (the second document must have an open sketch). Hold down Ctrl and drag the sketch entity into the second document. Release Ctrl, hold down Shift, and drop the sketch entity.
You can copy an entire sketch and paste it on a face in the current part, or you can paste it into a different sketch, or into a part, assembly, or drawing document. The target document must be open.
When you copy
an entire sketch using the Copy
Entities 
tool (Sketch toolbar), you can specify
to copy the relations.
To copy and paste a sketch:
Select the closed sketch in the FeatureManager design tree.
Click Edit, Copy, or press Ctrl+C.
Click in the sketch or document where you want to paste the center of the sketch.
Click Edit, Paste, or press Ctrl+V.