The default location for storing app data is /data/data/package_name.
If your apps require a lot of data, you can use the corresponding directory on your SDCard. In the Android Device Monitor, you can view the file system on your device and see where your apps are storing their data. Likewise, downloaded APKs and games go into the /mnt/sdcard/Android/data/ folder. Where do I find the data for my apps on Android? Generally, apps’ data is stored in the /data/app directory.