Hi,
Thank you for your question!
If you have contributed to your RRSP this year, then you would need your receipt from the financial institution that you invested with to claim your contribution. You should have received most of your slips and receipts by the end of February. If you haven't received your slips yet, you can consult the following page to request slips directly through the CRA .
Keep in mind that earnings from investments in RRSP do not typically need to be reported. According to the CRA website, you would typically only have to pay tax on RRSP withdrawals, not contributions.
Hope this helps.