Since each app that you've installed on your smartphone creates its own cache data, you'll have to go through each app one by one to clear its respective cache data. That's the official way ...

This simple tweak can make any device feel noticeably faster and more responsive, regardless of its make or model.

If your phone is running slower than you think it should, try clearing out the cache on your browser or most-used apps to bring it back up to speed.