Best way store confidental data is to use open source password manager apps, I personally use KeePassDX for android phones and keepass for Windows OS to store all my sensitive and confidential data.For frequent usage, I keep all of my credit/ Debit cards saved in Wapp with me. Its difficult to memorise 8 debit/Credit card info without fail. Suggest a better and safe way to store and use.
Please don't install this. This particular app might be safe but in general keeping card details as wallpaper is safer than installing unknown app from apkshare apk na, via dropbox or email