SIM Applications on iPhone X

[warlololock]

Today my dad got a used iPhone from a friend of his, and while going through the settings, he stumbled upon this thing called "SIM Applications". Think he clicked on a couple (there were things like Stocks, Finance, News etc) and some black translucent screens popped up (things like CNA alerts, reuters etc).

Asked me what it was and I have 0 clue seeing as I've never even clicked on that part of the settings menu before.

Quick google and apparently it's some sort of subscription service? Is there a way we can check if he has accidentally subbed to anything and if he will be charged for it?

Thanks and sorry for the noob question.

 

[PetPet]

I believe that's your carrier's services.
If I'm not wrong, it's a menu for you dial in to subscribe to them.

You'll need to check your telco bills to see if you've anything subscribed though.