How to receive a sound alert for e mail on iPhone 8+
Mail push/fetch is disabled in Low Power Mode, so you can't get an alert if you have that on.

To configure Mail push or fetch, go to Settings → Accounts &amp; Passwords → Fetch New Data and set your accounts to Push (if available) or Fetch instead of Manual. Fetch is only available on power and Wi-Fi so if you do not meet this criteria it will act as Manual anyway.