To export prefabs for Unity, Unity-created prefabs are saved via "Assets > Export Package" as .unitypackages (retaining dependencies), while external 3D models (e.g., Blender, Maya) are exported as FBX (using Unity’s default Y-up axis) then imported into Unity to create a prefab.
For Unity-built prefabs, the Export Package tool includes all linked assets (textures, scripts)—this ensures the prefab works correctly when shared.
For external models, FBX is the most compatible format. Matching the model’s scale and axis to Unity’s settings prevents distortion.
A key tip: Place textures in the same folder as the FBX when exporting external models. This makes linking materials to the prefab in Unity smoother.