Do wallet cards work on iPhone?

Both the iPhone and the Android card are built and share one design, so the colours and wording you set apply to both. Whether each is switched on is a platform-level thing rather than a per-restaurant setting, and your loyalty card page says plainly at the top which are live right now, so read that rather than this. Either way your design saves and is what the first card is issued with, and iPhone customers earn stamps regardless: the card is a window onto the stamp record, never the record itself.