Canadian law applies to foreign platforms
Even if a social media company is headquartered abroad, PIPEDA applies when it does business in Canada and processes Canadians' personal information. Commissioners have repeatedly asserted jurisdiction.
Requesting information, correction, and removal
You can request access to the information a platform holds about you.
You can request correction of inaccurate information.
Platforms must offer deletion options where legally required. Quebec's Law 25 includes a right to de-indexing (removal of links) in specific circumstances.
Unwanted posts about you
If someone posts private information about you without consent, you may have a claim for intrusion upon seclusion or public disclosure of embarrassing private facts in provinces that recognize these torts.
Non-consensual intimate images have their own criminal and civil regime (see Criminal Code section 162.1 and provincial NCDI statutes).