Hello,
I got study permit Extension few days ago. Received permit by mail also. Which address i send my passport for visa stamping?
Thanks
Study permit extension is a PERMIT in itself. it doesn't need any stamping on visa unless you applied for TRV.
For TRV they will ask you to send the passport for stamping when got approved.
So what I understand by your 2 line query is you got study permit extended and received the new permit in mail. So no further action is required by you at this time.
IF you want to apply for TRV (which is required only to re-enter Canada), its a separate application.
Good luck.!!