How to delete Cache and Junk files for APP's

I am using 6S 16 GB. Drastically increase memory size for APPs day by day. how to delete the cache and junk file in mobile. Do we have any app for that? Settings->General->Storage&ICloud usage->Manage Storage-> Here we will find the "Documents&Data"..Here Documents size increasing day by day.. pls suggest me how to delete those files..