Thank you. I read that document. I am working on my reference letters for my previous job. For the ties in Ontario, do I need to upload anything?
Depends on your ties to Ontario. If you have relatives in Ontario, you'll have to upload the documents as noted in "6. Relatives in Canada (if applicable)" in the checklist pages 47-48.
From the bottom of page 8 (page 13 of the PDF):
You will be required to list your established ties to Ontario. Ties to Ontario can include but are not limited to, the following:
Current and/or previous employment in Ontario,
Job offers or jobs applied/interviewed for in Ontario,
Education in Ontario,
Volunteer work in Ontario,
Lease agreements for a residence in Ontario or property ownership,
Professional networks and affiliations,
Family ties,
Social connections or personal relationships, and/or
Previous visits to Ontario.
From the checklist:
6. Relatives in Canada (if applicable)
Copies of the following documents if you or your spouse or common-law partner has a parent, grandparent, child, grandchild, sibling, aunt, uncle, niece, or nephew who is a Canadian citizen or permanent resident living in Canada aged 18 years or older:
Birth certificate of your relative,
Citizenship or permanent resident document of your relative, and
Evidence of your relative’s residency in Canada (i.e. property documents, employment documents, bank statements, tax documents that contain name, address and contact information, etc.).
I personally only have jobs I have interviewed for in Ontario for which I'll provide the email confirmations of the interview times, and I will mention the names of friends I have in Ontario and dates of previous visits to Ontario in the space provided for the answer. Note that from what others who actually have gone through the OINP application have told me, you have 1000 characters to list your ties in Ontario, where it will say "Please list all of your established ties in Ontario below (maximum 1000 characters)."
You can separately write a letter of intent that you upload in another section.