iPhone 8 is it possible to detect if it data was stolen

[j.a.s.o.n.]

is it possible to detect if someone used a spy app to steal data off my iphone....
would i be able to find a digital foot print of how they were able to access my iphone or any information they were able to steal.
or where that information was sent to?

thanks!

iphone 8 plus
ios 12.1.4

 

[Ledsteplin]

The odds of anyone putting something like that on your iPhone are pretty slim. They would first need to have possession of your iPhone. And I don't even know any app like that exists, except for maybe the FBI or the CIA.