Thaaank you i almsot tagged you your really only person off the top of my head who I know regularly uses iPhone. 😅
So the username is pretty flexible: it can be anything, and there’s no restriction on multiple people having the same own. It’s like a display name, for clients to show your “handle” in a sense, even though it can look a little different in different clients.
The nostr address (or NIP-05 ID) is a little more “unique”. It’s created by adding a DNS record on a particular domain that is linked to your specific npub. Some NIP-05s are free: someone owns a domain and will add the record for you, so you could then create yourname@theirdomain.com as your unique ID.
There are also providers, like the one I use, the OG nostrplebs.com from nostr:npub1g6ghj36a9y9d6p4vz4rq6z8rwrqxm6evllnlhkt26e55h9y0q6psv4hu7v (and nostr:npub12262qa4uhw7u8gdwlgmntqtv7aye8vdcmvszkqwgs0zchel6mz7s6cgrkj too, right?) where you can pay a few sats for the ID. This could also be used in a professional environment to be yourname@yourcompany.com which is *sort of* a loose proof of identity, at least with businesses where the domain is recognizable and access to the DNS is relatively secure.
Names/IDs/discovery of users is definitely still a work in progress on Nostr, especially because different clients have different levels of capability when it comes to search and tagging. But you can think of it as different ways to represent your account that can help other users find you (or sometimes not help, lol)
Anyway, hope *this* helps!
Discussion
Hahaha any time brother 🫂