After using for a while, your iPhone contains a lot of unexpected data such as junk and you might encounter storage problems. Look at our following solutions to clean up your iPhone 6 manually and then see how much space you can free up for storage saving.
How to check the usage of Apps on iPhone
You should check to see what is using the most space on your phone by: Access Setting > General > Usage > Manage Storage.
You are able to see how much space you you have used and the rest available. Moreover, you can see the list of apps with their corresponding usage on your iPhone. The report somehow indicates the usage situation for your wise decisions.
9 awesome tips to manually clean up iPhone to free up significant space
No cleaner application required, you can clean up iPhone your self easily in iOS.
If your iPhone is jailbroken already, you are able to take further steps to free up much more space. Look at our another topic: Manually Clean up iOS to fix lag on jailbroken iPhone.