Green text versus blue what does it mean?

Adding to my previous response, if you send a message to a user using iMessage (blue) and after a while it turns green, it is because the message failed to send. That can be because your or the recipients connection is unstable, the recipient has their phone switched off or for any other reason, really, that can prevent a message from going through.

Hello!

When you send a text message to a non-Apple user, the message appears green. That means that the message has been sent as an SMS, using your wireless carrier network.

When a text message appears blue, it is sent using iMessage. That means that both you and the other user have an iPhone, and therefore the message is sent using WiFi or Mobile Data instead of an SMS (picture it like WhatsApp or Messenger)... Sending a message using iMessage also gives you access to some additional features, such as reactions (aka TapBack), replying to a message, or thread, etc.

Here's some articles relevant to your question:

Messages for iPhone, iPad, Apple Watch, and Mac - Official Apple Support

Use Messages on your iPhone, iPad, or iPod touch - Apple Support

https://www.xfinity.com/hub/mobile/difference-between-imessages-and-sms-messages

Hope this helps!

-flef

the person you are texting with, or who you received a text from, does not have an iPhone. Also, if you know the person has an iPhone and your initial text is green, it means the phone is turned off, they are out of range, or they blocked you.