Let's find out with the help of iPhone Mail, which scours not only the messages it already knows but can continue the search on the server (if supported).
Search Mail in iPhone Mail
To find messages in iPhone Mail:
- Open the folder in which you suspect the sought message.
- Scroll to the message list's very top.
- Tap in the Search folder field.
- Enter the desired search term.
- Tap From to search sender names and addresses.
- Tap To to search recipients (in the To: and Cc: fields.
- Tap Subject to search the Subject: lines.
- Tap All to search message bodies in addition to sender, recipient and subject lines.
iPhone Mail 3 and 4 will only search the header lines, not message text.
- Tap Continue Search on Server… to search all mail in the folder, not just what iPhone Mail has downloaded before.
Search Across Folders in iPhone Mail
To search all your mail folders in iPhone Mail:
- Go to the leftmost Home screen.
- Swipe to the right to reveal Spotlight.
- Type the desired search terms in the Search iPhone field.
- iPhone Mail will search the From:, To:, Cc: and Subject: fields (but not message bodies) of all mail already downloaded to your iPhone, no matter the folder.
(Updated October 2011)