usually a face to face interview works best, there’s more spontaneity, memories, it’s easier for me as interviewer to follow up, there’s more room for intimacy, and it’s easier to to describe the environment where you were when something happened “oh, eh, I don’t know, I think the sun was shining, yes! yes it was! and…” it allows you to remember more easily - as I am not just interested in “facts” but more so in feelings, memory, your opinion, belief system, etc. It’ll also take you less time than if we would do it in written form (it would be a lot of forth and back, would require you to think about things harder).
But if you really want we can try the written form.