This article demonstrates the process of updating the iPhone’s SMTP Mail Settings.
1. Open the Settings App.
2. Select Passwords & Accounts.
3. Select the relevant Mail Account.
4. Select Account.
5. Select SMTP.
6. Select Add Server.
7. Enter in the relevant credentials. Then select Save.
8. Select Primary Server and change it to the the new SMTP Server you just added.
You have successfully added and modified the SMTP Server an iPhone.