Last updated on October 27th, 2026 at 09:34 am
To remove the subject field from text messages on an iPhone, open Settings, scroll to the bottom and tap Apps, tap Messages, then turn off Show Subject Field. The extra “Subject” line disappears from the box where you type, and new messages go out as one plain block of text.
Applies to: iPhone running iOS 18, iOS 26 or iOS 27 (the current version as of October 2026). On iOS 17 and earlier, Messages is listed directly in Settings instead of under Apps. The same Settings > Apps > Messages path appears in Apple’s guide to fixing problems sending and receiving messages.
What the subject field is
When Show Subject Field is on, the message box in Messages splits into two parts: a gray Subject line on top and the normal text area underneath. Anything you type on the Subject line is sent in bold above the rest of your message, a bit like the subject of an email.
Some people turn it on to get bold text or to label a message in a busy group chat, then forget about it. Others turn it on by accident and wonder why every text now has two lines. Either way, it is a single switch, and it applies to every conversation on that iPhone.
Turn off Show Subject Field (iOS 18 and later)
- Open the Settings app. Its icon is a gray gear, usually on your Home Screen or in the App Library.
- Scroll all the way to the bottom of the Settings list and tap Apps. You’ll see an alphabetical list of the apps on your iPhone.
- Tap Messages. You can scroll to the letter M or type Messages in the search field at the top of the Apps list.
- Scroll down past the iMessage options to the section labeled Text Messaging (on some versions it is labeled SMS/MMS). This section also holds switches such as MMS Messaging and Character Count, depending on your carrier.
- Tap the Show Subject Field switch so it turns from green to gray. The change saves immediately, so there is no Save button to tap.
Go back to Messages and open any conversation. The box at the bottom should now show a single line labeled iMessage, Text Message or RCS, with no Subject line above it.
If your iPhone runs iOS 17 or earlier
Older versions of iOS list each built-in app directly in Settings, so the Apps step doesn’t exist.
- Open Settings and scroll down to the group of Apple apps (Phone, Messages, FaceTime and so on).
- Tap Messages.
- Scroll to the SMS/MMS section and turn off Show Subject Field.
Not sure which version you have? Go to Settings > General > About and look at iOS Version. If you see an Apps entry at the bottom of Settings, use the steps in the previous section.
Can’t find Show Subject Field?
The most common reason is the Settings layout change in iOS 18. Many older guides still say Settings > Messages, and on a current iPhone that entry is no longer on the main Settings screen. Try these in order:
- Search for it. Swipe down on the main Settings screen to reveal the search field, then type Subject. Tap the Show Subject Field result to jump straight to the switch.
- Look under Apps, not at the top level. On iOS 18 and later, Messages lives in Settings > Apps, which is the last item in the list.
- Scroll further. The switch is in the text messaging section, below the iMessage, sharing and contact photo options. On some carriers that section is long.
- Check for a managed device. An iPhone set up by a school or employer can have some Messages options hidden or locked. Ask whoever manages the device.
Skip the subject for one message only
If you like having the subject field available but don’t want it on a particular text, you don’t have to change the setting. Simply leave the Subject line empty and type in the lower text area as usual. A message with a blank subject is sent like a regular text.
If you already typed something on the Subject line, tap it and delete the text before you send. For example, if you typed “Dinner Friday” as a subject to Jordan and meant it to be the message itself, cut it from the Subject line and paste it into the text area.
Why you might still see subjects
Bold lines in messages you receive
Your setting only controls the box you type in. If Priya has the subject field turned on and fills it in, her messages still arrive with a bold first line. There’s no setting on your iPhone that hides another person’s subject.
Older messages in a conversation
Turning the setting off doesn’t edit messages that were already sent or received. Any earlier text that had a subject keeps its bold header in the conversation history.
Texts to Android phones look odd
A plain SMS text has no place for a subject. When you add one to a green-bubble text, the message is typically sent as MMS, and some Android messaging apps show the subject as a separate line or a “Subject:” label. Turning off the subject field (or leaving it blank) avoids this. If MMS isn’t part of your plan, a text with a subject may also fail to send, so this is worth checking with your carrier if green-bubble texts get stuck. Attachments work the same way, which is why texting a contact card from your iPhone needs MMS Messaging turned on when the recipient isn’t using iMessage or RCS.
Your iPad still shows it
Messages settings are set on each device. If you also text from an iPad, open Settings > Apps > Messages on the iPad and check the same switch there.
The Subject line is still in the message box
Close Messages completely (swipe up from the bottom of the screen and pause, then swipe the Messages card away) and open it again. If the line is still there, restart the iPhone. If the phone is frozen and won’t restart normally, see how to force restart an iPhone.
Confirm the change, or turn it back on
To confirm, open Messages and tap the compose button (the square with a pencil) in the top-right corner. You don’t need to send anything: if the bottom of the screen shows a single text box, the setting is off.
To bring the subject field back, return to Settings > Apps > Messages and turn Show Subject Field on again so the switch is green. The Subject line reappears in every conversation right away.
Frequently asked questions
Does turning off the subject field delete any messages?
No. The switch only changes how the typing area looks. Your conversations, photos and attachments stay exactly as they were, including any old messages that had a subject.
Will the other person know I turned it off?
No. Nothing is sent to anyone when you change this setting. They’ll just stop seeing bold subject lines from you.
Can I keep the subject field for one contact and not others?
No. It is a single setting for the Messages app on that device. The closest workaround is to leave it on and keep the Subject line blank in the chats where you don’t want it.
Is there another way to get bold text without a subject line?
On current versions of iOS, Messages has its own text formatting. Select a word you’ve typed, then tap the formatting option to make it bold, italic, underlined or strikethrough. Apple explains this in its page on formatting text and animating messages.
Does this affect group texts?
Group conversations work the same with the subject field off. If you want to label a group, give it a name instead; our guide to creating a group text on iPhone covers naming a group iMessage.
Next step
While you’re in Settings > Apps > Messages, it’s a good time to make sure iMessage and Send as Text Message are set the way you want. If iMessage is off, our walkthrough on turning on iMessage shows where the switch is.
Matt Jacobs writes and maintains the guides on Support Your Tech, which he started in 2017. He spent most of his career keeping small-business PCs running and still takes the occasional consulting job, so the steps here come from fixing the same problems on other people’s computers. Every guide is checked on his own Windows 11, Windows 10, Mac, iPhone and iPad before it goes up.