what medium do you send your client work through?

i recently took photos for a friend (who also does modelling) and i'm wondering how to send him the photos. i generally only ever do photography for myself and i just edit it for instagram, but he might want to use these works for his own portfolio or something, i'm not sure, so i don't know what's the best way to send the photos through via /r/photography https://ift.tt/2v9GE5b