Creating a hologram in your Unity project is just like creating any other object in Unity. Placing a hologram in front of the user is easy because Unity's coordinate system is mapped to the real world - where one meter in Unity is approximately one meter in the real world.
1. In the top left corner of the Hierarchy panel, select the Create dropdown and choose 3D Object and Cube.
2. Select the newly created Cube in the Hierarchy panel
3. In the Inspector find the Transform component and change Position to (X: 0, Y: 0, Z: 2). This positions the cube 2 meters in front of the user's starting position.
4. In the Transform component, change Rotation to (X: 45, Y: 45, Z: 45) and change Scale to (X: 0.25, Y: 0.25, Z: 0.25). This scales the cube to 0.25 meters.
5. To save the scene changes, select File > Save Scene, name the scene, and select Save
Output