The Android Emulator runs inside Android Studio by default. This lets you use screen space efficiently, navigate quickly between the emulator and the editor window using hotkeys, and organize your IDE and emulator workflow in a single application window.
However, some emulator features are only available when you run it in a separate window. To launch the emulator in a separate window, go to File > Settings... > Tools > Emulator (Android Studio > Settings... > Tools > Emulator on macOS) and deselect Launch in the Running Devices tool window.