Resistors, current and voltage Help

[drgshahbaz1193]

I am a little confused about what a resistor does and what practical purpose it serves. could someone please explain that? Also how does the resistor affect current? I mean is the current coming out equal the current coming out?

Also kirkoffs rule says that voltage remains the same in a loop, how then does a resistor give us a drop in voltage?

I am really confused, help would be greatly appreciated.