This tutorial was written on iOS version 13.3. The exact prompts on other versions may vary.

• In Settings, scroll to Passwords & Accounts. Tap Add Account
• On the next screen, select Other, then Add Mail Account
• Fill in the details (examples below), then tap Next
  • Name Joe Bleaux
  • Email jbleaux@sdf.org
  • Password your SDF password
  • Description SDF Mail for Joe Bleaux (or whatever floats your boat)
  • You will need to fill in pretty much all the details by hand.
• For Incoming Mail Server section:
  • Hostname mx.sdf.org
  • Username jbleaux
  • Password your SDF password
• For Outgoing Mail Server (MetaARPA Users Only!)
  • Hostname mx.sdf.org
  • Username jbleaux.sdf.org@sdf.org
    • This will be the URL you have set up if you have a custom one. If not, then model it after this example.
• Password your SDF password
• Click Save on the next screen.
• Select the account from the Passwords & Accounts screen. On the next screen, Tap Account (which will show your username (jbleaux@sdf.org)
• Scroll down and click Advanced.
• Under Incoming Settings, tap to enable Use SSL, and for Server Port, put 993.
• Tap SMTP (Under Outgoing Mail Server), to view outgoing mail options, then tap the Primary Server (should be mx.sdf.org. Change Authentication to MD5 Challenge-Response. Click Done at the top.
• Tap <Account at the top to go back, then tap Done.

You should be sending and receiving your SDF mail on your iPhone!