What iMessage is and how to turn it on
iMessage is Apple's messaging service that sends text, photo, and video messages over Wi-Fi or cellular data instead of using your phone's SMS plan. When you send an iMessage to another Apple device, the message appears in blue; regular text messages appear in green. You turn iMessage on in your device's Settings, and it works automatically once enabled — you do not need to do anything special to send or receive messages.
iMessage requires an Apple ID and works across iPhone, iPad, Mac, Apple Watch, and iPod Touch. If you have multiple devices, you can receive messages on all of them at once, or choose which devices should receive iMessages. The service is included with your Apple device at no extra cost.
Key Takeaways
- iMessage turns on in Settings under Messages, and you sign in with your Apple ID.
- You can choose which phone number or email address people use to reach you, and add multiple addresses if you want.
- If you have more than one Apple device, you can receive iMessages on all of them or turn off iMessage on specific devices.
- Turning iMessage off on your iPhone does not affect Messages on your Mac or iPad — each device has its own setting.
Turning iMessage on for the first time
Open Settings on your iPhone or iPad, then tap Messages. Toggle the iMessage switch to on (it will turn green). Your device will connect to Apple's servers and verify your Apple ID. This usually takes a few seconds. Once the switch is on, iMessage is active and ready to use.
If you see a message saying "Waiting for activation," your device is still connecting. This can take up to a minute on a new device or after a factory reset. Keep the Settings app open and wait — do not close it or restart your device. Once activation completes, the toggle will show as on and you will see a checkmark next to your phone number or email.
Choosing which contact information people use to reach you
In Settings > Messages, scroll down to find "Send & Receive." Tap it to see all the phone numbers and email addresses linked to your Apple ID. The addresses shown here are the ones people can use to send you iMessages. By default, your phone number is checked. You can also check any email addresses associated with your Apple ID.
If you want people to reach you at an email address instead of your phone number, check that email and uncheck your phone number. If you want both, check both — people can use either one. The phone number or email you select under "Start Conversations From" is what appears as your sender address when you send a message. You can change this at any time without affecting messages you have already sent.
Setting up iMessage on a Mac
On a Mac, open System Settings (or System Preferences on older macOS versions), then click Messages in the sidebar. Check the box next to "Enable Messages in iCloud" or sign in with your Apple ID if prompted. Your Mac will verify your account, which usually takes a few seconds.
Once signed in, go to Messages > Preferences (or Settings) and click Accounts. Select your Apple ID account and check which phone numbers and email addresses you want to use for iMessages on this Mac. You can use the same addresses across all your devices, or use different ones on different devices — it is your choice. If you want your Mac to receive all the same iMessages as your iPhone, make sure you use the same phone number or email on both devices.
Receiving iMessages on multiple devices
If you own an iPhone and a Mac, or an iPhone and an iPad, you can receive the same iMessages on both devices. To do this, use the same phone number or email address in the "Send & Receive" settings on each device. When someone sends an iMessage to that number or address, it will show up on all your devices at once.
If you do not want iMessages to appear on a specific device — for example, you want them only on your iPhone and not on your iPad — go to Settings > Messages on that device and turn off the iMessage toggle. The device will stop receiving iMessages, but you can turn it back on anytime. Turning iMessage off on one device does not affect the others.
Troubleshooting iMessage activation problems
If iMessage stays stuck on "Waiting for activation," first check that you are connected to Wi-Fi or have cellular data turned on. iMessage cannot activate without an internet connection. If you are connected, try turning the iMessage toggle off and back on again. Wait 30 seconds between each step.
If activation still fails, sign out of your Apple ID in Settings > [Your Name] > Sign Out, then sign back in. This refreshes your account connection. If the problem continues, restart your device by powering it off completely and turning it back on. If you still see an error after these steps, check Apple's System Status page to see if iMessage servers are having problems in your region.
Why iMessage might show as unavailable for a contact
Sometimes you will see "Not Delivered" under a message or the message will send as green (SMS) instead of blue (iMessage). This usually means the person you are texting does not have iMessage turned on, or their device is not connected to the internet. You can still send them regular text messages — the message will just use your phone plan's SMS instead.
If someone has turned off iMessage or removed their phone number from their Apple ID, you cannot reach them through iMessage. They will receive your message as a regular text instead. This is not an error — it is how the system works when the other person is not using iMessage.
Frequently Asked Questions
Can I use iMessage without a phone number?
Yes. If you have an iPad or Mac without a phone number, you can still use iMessage with an email address. People will send messages to your email instead of a phone number. You can also add an email address to your iPhone's iMessage settings so people can reach you that way too.
What happens to my iMessages if I turn off iMessage?
Your old iMessages stay in the Messages app — turning off iMessage does not delete them. New messages from people will arrive as regular text messages (green) instead of iMessages (blue). If you turn iMessage back on later, new messages will be blue again, but old green messages will stay green.
Do I need Wi-Fi to use iMessage?
No. iMessage works over Wi-Fi or cellular data. As long as your device is connected to the internet in some way, you can send and receive iMessages. You do not need a cellular plan, but you do need an internet connection.
Can I use the same Apple ID for iMessage on two different iPhones?
Yes, but both phones will receive the same iMessages. If you want to keep messages separate between two phones, use different Apple IDs or different phone numbers in the "Send & Receive" settings on each phone.
Why is my iMessage showing as delivered but the person says they did not get it?
A "Delivered" notification means the message reached Apple's servers, but it does not may provide the other person saw it. Their device may not have downloaded it yet, or they may have notifications turned off. Ask them to check their Messages app — the message should be there. If it is not, they may have iMessage turned off or their account may have a problem.