The Tatoshi Wallet is a non-custodial wallet. This means your private key is stored solely on your device. If you would like to change your device, you need to transfer your private key and your protector data to your new device. Tatoshi Wallet provides a functionality for this. In the menu “More” -> “Backup” you will find the function “device change”. Follow the instructions until the qr-code is displayed. Then download the app form the Appstore on your new device. Select “Recover” on your new device an follow the instructions.