show carrier name on status bar (galaxy A5 2016)
I've been trying to do the same to my devices, and after extensive searching it looks like the only way out is to root and modify the SystemUI yourself. Refer here and here for steps on how to do this. This still works as of Android 6.0.

This will be even harder to do on Samsung phones, because their framework is tightly integrated and you might not even be able to decompile the framework in the first place.