What AdMob requires
The AdMob Publisher Policies (Section "Privacy disclosures") require you to: (a) post a clearly labelled privacy policy, (b) disclose third-party ad serving by Google AdMob and ad partners, (c) include information about cookies, mobile ad identifiers, and similar technologies, (d) describe options to opt out of personalised advertising, and (e) link to How Google uses information.
Ad personalisation and consent
If your app shows ads to EU/UK users, you must collect GDPR consent and pass it to AdMob via the User Messaging Platform (UMP). Without UMP, AdMob serves only non-personalised ads to EU traffic, which dramatically reduces eCPM. Your privacy policy must mention that consent is collected and may be withdrawn in the app settings.
iOS App Tracking Transparency
If you show personalised ads on iOS 14.5+, you must call requestTrackingAuthorization() before initialising AdMob. Your privacy policy must say: "We use Google AdMob to show ads. With your permission, AdMob accesses the iOS Identifier for Advertisers (IDFA) for ad measurement and personalisation. You can deny or revoke permission in Settings → Privacy & Security → Tracking."