If you are not rooted, make sure in settings you have enabled Google backup. Once you get your new phone and login with Google account select restore and it will auto download all your apps. But it will not download the app data. There are other solutions like backup apps like helium and titanium backup. I know helium works without root not sure about titanium backup. If you are rooted titanium backup is the best out there and it will restore all the apps and it's data.
The stock Google backup and reset is not good, but that's all we have currently. Hopefully it's better in the next version and we can restore app data as well from Google restore.
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