iMac

so i reinstalled ios on my mac because i had previously downloaded windows bootcamp but it wouldnt let me switch back to ios so i decided to wipe the whole thing and restart. After force restarting and confirming to install ios, there is a section where i need to fill in my iphones password as some kind of confirment? Not sure but my imac has been stuck on this screen for about 3 hours. what do i do