# Creating UI in Unity
There are two locations where UI interactions can happen:
- Screen Space
This UI can be compared with the UI of a normal mobile application. All widgets will be drawn ontop of the 3D world. For smartphone AR applications this is the most usefull.
- API Documentation: https://docs.unity3d.com/2021.3/Documentation/Manual/UIElements.html
- UI Builder Documentation: https://docs.unity3d.com/Packages/com.unity.ui.builder@1.0/manual/index.html
- Video Tutorial: https://www.youtube.com/watch?v=8w0qvO4Vumc

- World Space
This UI is used when the UI is a 3D object itself. All widgets are objects in the 3D world. This UI type of interaction is most usefull in Mixed Reality (hollolens) and/or VR.
- Documentation: https://docs.unity3d.com/2021.3/Documentation/Manual/UICanvas.html
- Video Totorial: https://www.youtube.com/watch?v=GuWEXBeHEy8
