You need 3 types of documents:
1) Proof of eligible immigration status -> stamped CoPR, PR card, etc
2) Proof of residency -> monthly bank statement, lease agreement, ON driver's licence, etc
3) Support of identity -> Passport, etc.
Take a look at http://www.forms.ssb.gov.on.ca/mbs/ssb/forms/ssbforms.nsf/GetFileAttach/014-9998E-82~1/$File/9998-82E.pdf for the details. If it takes a bit of time to collect them, don't worry. The 3 month waiting period starts from when she became an Ontario resident, not from when she applies.