How can I, using Finder, enter an "app". Not open, enter

Apps in macOS are not .exe files, they are folders with special rules, but folders. I can, use ⇧⌘G and paste the path towards and past the app. But that is beyond inconvenient. So, scenario: I am in Finder and I reach the app. I want to go past the app, into the underlying folder structure. What do I do?