What is Resistor and it's types

I have taken an example of a pipe or drain to explain Resistor ,so in this some people will think that if both side pressure is the same then how the water is flowing!!, which is absolutely correct and I appreciate this kind of thinking 😊.But please don't confuse I didn't take the entire pipe or drain 😃.I have taken only a cut of pieces of pipe and in this case if you will take any two points then pressure will be the same.
Thank you ☺️.