This setting in the iOS and Android FOREVER® mobile app allows users to work inside the app without using their phone carrier’s data plan. Please note that the performance of both versions of the app may suffer if in an area without strong Wi-Fi connection.
You can check on this setting by completing the following steps...
iOS (Apple) products: https://support.apple.com/en-us/109323
Android products: https://www.samsung.com/uk/support/mobile-devices/how-do-i-enable-or-disable-mobile-data/