https://eais.rkn.gov.ru/en/feedback/
At the same time, there's not only a website form, but Android and iOS apps in Google's and Apple's stores (they are only linked on Russian version of reporting form)
https://play.google.com/store/apps/details?id=org.rkn.ermp
https://apps.apple.com/ru/app/%D1%80%D0%BA%D0%BD/id151197061...
Just curious, if it's OK for Google and Apple to support Russian censorship, especially anti-LGBT one.