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 or press Ctrl+C.
- Click in the sketch or document where you want to paste the center of the sketch.
- Click or press Ctrl+V.