How long iPhone can keep my email message?How to setting the period time to keep my email longer?
I want to keep my email longer in my iPhone. How many email iPhone can keep my email.
Longer than what?
Assuming you're using IMAP (most email accounts are nowadays), there is no limit as far as the phone is concerned - the limit (if any) is imposed server-side.
On my phone right now I literally have over 10,000 messages going back at least 5 years (probably more if I cared to look)