do they have access to google play?: https://play.google.com/store/apps/details?id=com.bitchat.droid
if google play is banned or they don't want to use it, they can get from github: https://github.com/permissionlesstech/bitchat-android/releases/download/1.5.1/bitchat-1.5.1.apk
they if they apple there is only one choice: https://apps.apple.com/us/app/bitchat-mesh/id6748219622
if google play is banned or they don't want to use it, they can get from github: https://github.com/permissionlesstech/bitchat-android/releases/download/1.5.1/bitchat-1.5.1.apk
they if they apple there is only one choice: https://apps.apple.com/us/app/bitchat-mesh/id6748219622