Several apps are dedicated to cleaning junk and temp files off your phone. While you can use a third-party app, Google has its own Files app that does the task well on Android phones. Just follow these simple steps:
Open Files by Google on your Android device,
On the bottom left, tap Clean.
On the Junk Files banner, tap Clean.
You can also select log files or temporary app files you want to delete,
Once the confirmation pops up, tap Clear.