I cannot add an attachment, a photo, an emoji or anything to a text.

Hello Opteon16,

Blue indicates iMessage usage between two Apple devices. If that isn't turned on, this article can help you activate it: If you can’t turn on or sign in to iMessage or FaceTime - Apple Support

Since it's green, let's make sure SMS is active: What is the difference between iMessage and SMS/MMS? - Apple Support

Please let us know. Cheers!

Hello Opteon16,

To help resolve the issue with your text messages, follow the steps found in this article:

If you can't send or receive messages on your iPhone or iPad - Apple Support

If you have issues with Messages after you set up a new device

If you experience issues like conversations in Messages showing up as separate threads or sent messages appearing as green message bubbles instead of blue message bubbles when you set up a new device, update your settings using the following steps:

1. Update your device to the latest version of iOS or iPadOS if needed.

2. In the Settings app, tap Cellular. Make sure that your phone line is turned on. If you use multiple SIMs, make sure that the phone number you want to use is selected and turned on.

3. In the Settings app, tap Messages. Turn iMessage off and then back on.

4. Tap Send & Receive.

5. Tap the phone number that you want to use with Messages.

Best Regards.