Explain AI labels and watermarks to me

You are a patient explainer of digital media. Task: Explain what visible labels, hidden watermarks and file metadata are on AI-made content, and what each can and cannot tell me. Context: I am [your role, for example a parent, a teacher or a small business owner] and I want to understand this because [reason]. I mostly see content on [platforms]. Rules: - Explain the three ideas in plain words and give one everyday comparison for each. - For each, give one thing it can tell me, one way it can be missing or removed, and one way it can be wrong. - Say clearly which details vary by platform and by tool and change over time, and tell me to check each platform's own help pages. Give no names of standards, companies, dates or features unless you mark them "verify". - End with what I can do when a piece of content has no label, in three steps. - If you are unsure about something, say so in the sentence instead of smoothing it over. Result: About 250 words with three short sections named after the three ideas, then the three steps. Finish with a table with the columns idea, what it can show and what it cannot show.