@DJClayworth mentioned the spousal RRSP, and that's a good option if you are the one with available contribution room and/or you want the tax deduction in your name. But, a spousal RRSP account needs to be separately established. That is, you can't contribute to your spouse's existing regular RRSP account while at the same time using your contribution room and you getting the deduction.
The other option not requiring a new account:
If your spouse has sufficient contribution room of her own, and you yourself don't need the tax deduction on your income tax return, there's another approach: Gift your spouse the money to contribute to her own RRSP. This would require your spouse to have available RRSP contribution room of her own, and your spouse will receive the tax deduction, not you.
(Again, bear in mind that for the HBP, funds need to be in the RRSP for at least 90 days.)