How to Add a Subject Field to iPhone Messages

Adding a subject field to iPhone messages is not currently supported by the Messages app. However, there are a few workarounds you can try to achieve a similar result:

1. Use the first line of your message as the subject: When composing a new message, start by typing the subject on the first line, followed by a colon, and then your message. This way, the recipient will see the subject line first before reading the rest of the message.

2. Use the Notes app: If you need to send a longer message with a subject, consider using the Notes app. Type your message in the Notes app, and then share it with the recipient via the Messages app.

3. Use a third-party messaging app: There are several third-party messaging apps available on the App Store that support a subject field, such as WhatsApp, Telegram, or Signal. You can try using one of these apps instead of the native Messages app.

Note: Keep in mind that if you use a third-party messaging app, both you and the recipient must have the app installed on your devices to communicate.