Questions about installing apache and nginx on one machine

I am confused about installing apache and nginx on one machine. Today I want to install apache and nginx on my own machine at the same time. This is certainly not a problem, but I am confused about one problem, when we open a Web page, which of the following is the function? During the original installation, the default listening ports of nginx and apache are both port 80, so nginx and apache can only start one, then the final result is who starts and who provides the service. Later I thought about how to change the nginx listening port so that both of them can get up. Who will provide the service in the end? Originally, port 80 is open for http by default. The ip Address: port of a website can be accessed, but port 80 provides services by default. Therefore, if apache or nginx listens to port 80, the port is omitted, all the questions are clear.