Ask an iOS signed application to run an unsigned application on a damaged device

I came across the following iOS jailbreak detection message:

How to determine if an iOS application is running on a jailbreak phone?

I would like to understand how to do what one poster suggested: GregH suggested combining an unsigned / incorrectly signed executable file inside a signed executable file and see if it can be successfully executed (executed) on the device. My question is: how do I get one application to execute another within myself? Especially in the sense that a device that is not jailbroken will complain / give an error. I assume that getting it inside another application is quite simple: just create one application and put it in the directory of another. If this is naive, I would also like to know how to do it right.

I understand that any solution will not be approved by the App Store.