You cannot do it on that version of Android. You would need to be running at least "Marshmallow". That said, you could move other files (music, photos, videos, etc.) over to the SD card to get you more space.
I would also suggest clearing the history, cache, etc., of many apps you use (like the browser) and even your Facebook, messaging, etc. As long as it isn't something you absolutely need, you can clear it out.
Next would be uninstalling any apps you don't actually use nor need.
Once you have done all of the above, restart the phone (turn it off and back on) and you should have a bit more room.