On a formal invitation, you would write "12:00 p.m." or simply "12:00 noon" to indicate twelve noon. It is best to avoid using "12:00 AM" or "12:00 PM," as they can be confusing. For added clarity and formality, you might also consider spelling it out as "twelve o'clock in the afternoon."
Twelve O'clock Noon
Entre mediodia y las cuatro (de la tarde = in the afternoon, p.m.)
12am is midnight. 12pm is noon.
It is noon when both the clock's hands are on twelve and the sun is overhead.
high noon, noon, noonday, noontide, noontime, twelve noon
noon
Noon.
11:48 am
Her husband had died at noon after sobbing twelve times.
On the same day it is 12 hours
Twelve noon is 12:00 PM. It is the middle of the day when the sun reaches its highest point in the sky.
Noon is PM, midnight is AM.