How to Set Up iMessage on iPhone or iPad

iMessage is text messages for iOS devices such as iPhone or iPad.
When you use iMessage and send a text message to someone with an iPhone or iPad and using iMessage on a Mac, the message will appear blue.

To set up iMessage, you'll have to go to settings and select messages. On the message page, you can activate the slider to activate iMessage.

You'll have to wait for the iMessage activation to complete. This can take up to 24 hours in some cases.

You can change some settings on this page as well. Keep messages is a useful option to change if you don't want messages to take up too much space on your iPhone.

You can also do the same thing for audio messages.
You can also activate this option inside of iCloud if you want to use iMessage across your devices.

If you get an activation error, try to sign out of apple id and restart your phone.

You can also turn your phone to airplane mode and back again to make sure your wifi or data is working correctly.
Finally, you can go to general settings and reset network settings and restart your iPhone.