Looking for help with Iron Boulder & Iron Crown

I want to register Iron Boulder & Iron Crown in my Pokémon Home app. I don't want to keep them I just want to get them registered to have the dex completed. I'm not sure if trading through the app or through Scarlet/Violet is the better method.

Can anyone help me with this? It would be greatly appreciated 🙂 Let me know if you're looking for anything that I can help with.