I have to run now, and I have to hide — my iPhone. It's just that I'm composing an email right now, and I don't want to lose what I have tapped so far.
Fortunately, it's easy (albeit maybe not in immediately obvious a manner) to save an email as a draft in iPhone Mail for later continuation.
Save a Message as a Draft in iPhone Mail
To save a message draft in iPhone Mail:
- Tap Cancel while composing an email message.
- Now tap Save.
To continue composing, go to the Drafts folder and tap the draft.