How so I see which app is using all my data?

[bigsapper]

My daughter's phone (iPhone6+) has seen a marked increase in the data usage recently including using almost 5GB in one day. She is not aware what app she has that might be doing this. Is there a way to know how much data a specific app is using?

[Weth · Accepted solution]

Settings / Cellular

Scroll down until you see a list of apps, Some apps will have a number, that is how much data it has used since last manual reset. If you scroll all the way to the bottom, there is the reset statistics button to set everything to zero and then monitor from there.

[bigsapper]

Thanks!