To add hair and eyes to a 3D model without manual rigging, use pre-rigged assets or AI/automated tools that handle rigging automatically.
Pre-rigged hair/eye assets come with built-in rigs—simply import them and attach to your model (e.g., parent hair to the head bone, align eyes to sockets).
AI/automated tools like Blender’s Hair Particle System (with auto-rig plugins) or Mixamo generate rigs quickly, great for beginners or fast projects.
For Blender, try the Hair Tool add-on (with auto-rig) for hair; use pre-rigged eyes from stores like Blender Market—match scale, align to sockets, and parent to the head bone.