Personally I delete PageController altogether and beside that have controllers namespaced under Controller namespace like
MyApiWeb.Controllers.Contact etc. PageController is just a name, you can do with it anything you want. There is totally 100% nothing special to the name PageController. It’s named PageController by default, because it’s serving a simple web page by default (and by default I mean, until you you write your own logic and controllers) It could be named SiteController, or MainContoller, or ChangeMyNameToWhateverFitsYouContoller.
PS. Actually there are no proper namespaces in Elixir but that is something totally out of scope, and by namespaced I mean having the same prefix