What uses the most data on these phones

Question

My step daughter goes over her monthly data allowance every month, I'm not sure what she is doing that is using so much of the data, does anyone have any ideas

Answer 1

The phone does not use data from your allowance if she is using wifi. Make sure she is logged on correctly.
You may all be on FB and Instagram, but do you use it in the same fashion and as regularly as your daughter? You can both be on FB, but if she uses it for 3-4 hours and you use it for 30 minutes, the usage will not be the same. Do you use FB while riding school bus? Does your daughter? No wifi on school bus I would wager. Does your daughter watch videos posted on FB? If not on wifi at the time, that uses a LOT of data.
Do you post as many photos on Instagram as your daughter? I know I certainly don't. Each of those photos use data to upload unless done so via wifi.
You may ALL be on certain apps, but I doubt you use the app in the same fashion as a teenage daughter UNLESS you have gone over with her how she should be using it to stay within a set data limit.
You asked for ideas on what could be using data. EACH of the apps I mentioned COULD be using data. Doesn't mean they are, it all depends on how the app is being used. Different people use apps differently. Simply because one person does not use data on an app does not mean another could be using a lot of data on the very same app.
Other sources for large amounts of data usage would certainly be iTunes. Does she download music, podcasts, videos, etc... while using cellular data? That would consume a LOT of data.