Sample Formula for Easter Standard Timezone(GMT or UTC – 4):

IF( HOUR(TIMEVALUE( CreatedDate - 4/24 ) ) < 12, "Morning",
IF( HOUR(TIMEVALUE( CreatedDate - 4/24 )) < 16, "Afternoon", "Evening" ) )

Output:

If the time is less than 12 PM, it will show as Morning.

If the time is greater than or equal to 12 but less than 16(4 PM), it will show as Afternoon.

If the time is greater than or equal to 18, it will show as Evening.