How do you complain about a news report?
Through the outlet first, then the relevant regulator — and the order matters, because regulators will almost always refuse a complaint that has not been put to the publisher.
Step one: the outlet. Contact the editor, corrections desk or readers' editor. Be specific: the headline, date, URL, the exact words complained of, why they are inaccurate or unfair, and what you want — a correction, an amendment, a right of reply, or removal. Most successful outcomes happen here, quickly and without formality, because publishers would rather amend than face a regulatory finding.
Step two: the regulator, if the outlet does not resolve it. Which one depends on the medium:
Broadcast is regulated by a statutory body covering accuracy, due impartiality, fairness and privacy, which can impose sanctions including fines and, ultimately, licence action.
Press is regulated by self-regulatory bodies in many countries, handling complaints about accuracy, privacy, harassment, and reporting of grief or children, and requiring publication of adverse adjudications.
Advertising content, including sponsored material, falls to the advertising regulator.
Some publishers belong to no regulator at all, in which case only legal routes remain.
What complaints usually succeed on: demonstrable factual inaccuracy; a headline not supported by the article; failure to distinguish comment from fact; intrusion into grief or privacy without public interest; and inadequate opportunity to respond.
What usually fails: disagreeing with an opinion; disliking the tone or the emphasis; objecting to a story being covered at all; and complaints about bias unsupported by identifiable inaccuracy — partiality in the press is generally permitted, while inaccuracy is not.
Deadlines are short, frequently a few months, so act promptly.
The separate legal routes — defamation, privacy, data protection and the right to erasure — are slower and costly, and a regulatory complaint is free.
If you are in the story, a right of reply request before publication is far more effective than a correction afterwards.
General information; bodies and rules vary by country.