Atomex wallet is a mobile app with an in-built conversion tool for multiple currencies. Atomex is Android compatible whereas an iOS version is coming. 

Conversion between crypto coins is anonymous and implemented on-chain in the form of atomic swap, or a peer-to-peer exchange between two parties without any agent being involved. Users have a control over their private keys. Usually, this kind of swap does not take more than several minutes. 

You can stake Tezos with Atomex.