.
a.m. = from 00:00 to 11:59.-- OK
p.m. = from 12:00 to 23:59.-- OK
In relation to 12:00 (midday or noon) can I also write 12:00 a.m.?-- No, it is normally 12:00 PM
And for midnight, is it okay 12:00 p.m.?-- No, it is normally 12:00 AM -- Just notice what you yourself w