You can only contribute to a RRIF by directly transferring certain types of payments you receive or are considered to have received.
You can have property transferred to your RRIF directly from:

your unmatured RRSP
your matured RRSP, including a direct transfer of a commutation payment from your RRSP annuity; an unmatured RRSP under which your current or former spouse or common-law partner is the annuitant.

You cannot transfer any part of your retirement allowance to a RRIF.