1. An unrated app is not publishable on Google Play. The Content Ratings policy states: "All apps must have a content rating from the IARC to be on Google Play. You must accurately complete the Play Console questionnaire for every app, and keep it updated if content in the app changes." And: "We don't allow apps without a content rating on Google Play." "Apps without a content rating will be removed from the Play Store." (https://support.google.com/googleplay/android-developer/answer/9898843)
2. Where the questionnaire lives and how it flows. "Open Google Play Console and go to the App content page (Policy > App content). Review the information about the questionnaire and enter your email address. Your email address will be used for correspondence with International Age Rating Coalition (IARC). Select a category and click Next." You can pause and resume later - "Each app can have one draft questionnaire at a time" - and the Summary page shows the calculated ratings before you click Submit. (https://support.google.com/googleplay/android-developer/answer/9859655)
3. The questionnaire is mandatory in three situations, not only at first submission: "You need to complete the content rating questionnaire for both your new and existing apps, including: New apps submitted to Google Play Console; Existing apps that are active on Google Play but lack a rating; All app updates where there has been a change to your content or features that would affect the responses to the questionnaire." (https://support.google.com/googleplay/android-developer/answer/9859655)
4. A false declaration is a policy violation, not a formality to rush through. "Misrepresentation of your app's content may result in its removal or suspension, so it is important to provide accurate responses to the content rating questionnaire." The help article adds: "App updates and submissions can be rejected for misrepresenting an app's content." (https://support.google.com/googleplay/android-developer/answer/9859655)
5. One questionnaire, many independent authorities - so the same app can carry different ratings by territory. "Your app's content ratings are assigned by separate rating authorities and determined by your questionnaire responses. Because they are independent third parties, each rating authority uses its own methodology to assign ratings." Hence: "Your app can earn different ratings in different territories because rating standards can have differences by territory." An authority can also override the calculated result: "Rating authorities participating in IARC may change your app's rating after a review. If a rating authority overrides your app rating and you want to update your responses, you'll need to complete the questionnaire again." If the calculated ratings no longer fit your content, retake it - "Click Start new questionnaire on the Content rating page." (https://support.google.com/googleplay/android-developer/answer/9859655)
6. What the rating actually decides. Content ratings "help filter or block your content in certain territories or to specific users where required by law, and determine your app's eligibility for special developer programs." In the European Economic Area, Australia, Brazil, Singapore, Switzerland and the United Kingdom, for users determined to be minors, mature content (18+ rated apps or games) is blocked from acquisition and purchase, and mature content is blocked or filtered from Play search and browse pages except through deep linking. (https://support.google.com/googleplay/android-developer/answer/9859655)
7. Ads are outside the rating but still bounded by it. "The content rating assigned to your app is specific to the content within your app. It does not include other features and practices, such as consumer agreements or ads." However, "any ads that appear in the app must not be significantly more mature in content than the primary content within the app itself" - set ad filters so campaigns only serve content matching your rating (for AdMob, use blocking controls and the ad content rating). (https://support.google.com/googleplay/android-developer/answer/9898843 / https://support.google.com/googleplay/android-developer/answer/9859655)
8. Re-run the questionnaire proactively after feature changes, not after a warning email. The policy is explicit: "If you make changes to your app content or features that affect the responses to the rating questionnaire, you must submit a new content rating questionnaire in the Play Console." Practical triggers: adding user-generated content or social interactions, introducing new content categories, adding interactive or purchase features, or changing what ads may show. (https://support.google.com/googleplay/android-developer/answer/9898843)
9. Disagree with the assigned rating? Appeal to the rating authority, not to Google Play support: "If you object to the rating assigned to your app by a participating IARC rating authority, you have the right to appeal directly using the link provided in your certificate email." Non-appeal IARC questions go through their own website (https://www.globalratings.com/). (https://support.google.com/googleplay/android-developer/answer/9859655)