NEM Mobile Wallet is a lite client app and allows managing multiple NEM accounts on the device.
Private keys and data are locally stored on the user’s device. It’s possible to import and export wallets, using the mobile app. With the NEM Mobile Wallet, one can send signed multi-signature transactions.
NEM Mobile Wallet is an open-source product designed by the NEM Mobile Team. The app is provided under the MIT license while the NEM team is not responsible for its malfunction.
It was a good step to start using this Wallet. You won't find better for nem. It's got the design as the exchange, using the same platform.