Whether it's email or the message function of SNS, the date and time must be in a proper format to be communicated to the other party. For example, if you want to tell 4:30 pm as the meeting time, writing "430" may be interpreted as 4:30 am depending on the context, and it may not convey your intention in the first place. It should be written as "4:30 pm" or "16:30" without abbreviating it easily.
However, it is common to spell dates and times by mixing Arabic numerals and Chinese characters, such as "April 1st" and "16:30", and it is quite troublesome to enter them on the iPhone. .. It can be fully communicated in formats such as "4/1" and "16:30", so it would be one way to think about it.
But you don't have to compromise easily. On the iPhone, there is a speedy way to enter spelling that mixes Arabic numerals and Chinese characters, such as "April 1st" and "16:30".
The procedure is simple, switch the software keyboard to Japanese input mode, and enter the numbers excluding "month" and "day" for the date and "hour" and "minute" for the time. "41" for April 1, "1029" for October 29, "525" for 5:25, "1745" for 17:45, and so on. If the fraction is a single digit in the time, you can enter it as it is, except for the two-digit notation such as "01" and "09". All you have to do is tap "○ month ○ day" or "○ hour ○ minute" displayed in the conversion candidate column.
In addition, this input method has a check mechanism, and impossible dates / times are not displayed in the conversion candidate column. For example, "132" cannot be January 32, so "1:32", and "2543" cannot be date / time, so only full-width / half-width numbers are available.