PSA: the 'official' Mastodon apps for iOS and Android are under-developed and not fully featured. You may want to try the community-made apps instead that have been around for years already and are established and work well. on iOS, try MetaText, and on Android, try Tusky - though you can also just pin the web browser to your home screen as a web app and it functions like a fully featured app with push notifications. :)
