Articles that help you develop Appium GUI tests your iOS app
If you are considering Appium or any other GUI testing framework for iOS, like XCUI Tests, then the first thing you should do is start using accessibility identifiers. Without them, your test scripts will be much more brittle.
When you make GUI tests using XCUI directly in Xcode, it will automatically build the app for you when you run the test. Appium, however, is run completely outside of Xcode, so you must supply a build for it.