Instantiate is Unity’s method for creating a new object at runtime, usually from a prefab. A common form is Instantiate(prefab, position, Quaternion.identity), which creates a new scene instance at the given position with no rotation. (course lab series, see source-csharp-unity-labs)
Store the returned object if later code needs to name, parent, configure, track or destroy that specific instance.
Related: unity-prefabs-scripting, prefab, prefab-vs-scene-instance, gameobject