If you have not "overcontributed" to your RRSP's (purchased more than your RRSP contribution limit), and you don't want to use the entire contribution on this year's tax return, you still need to report that contribution on this tax return, then "carry it forward". You can then choose to use the deduction on a future year's tax return.
https://turbotax.community.intuit.ca/replies/2647902