Q: I am in a group chat with people who all have iPhones but i am the only one in text message

Hey Cara Moranzoni,

Thanks for the question. If I understand correctly, you want to send messages using iMessage instead of SMS. I would recommend that you read these articles, they may be helpful in troubleshooting your issue.

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

1. Go to Settings > Messages. Check that the type of message that you're trying to send is turned on (iMessage, SMS, MMS, or Group messaging):
   

iOS and OS X: Link your phone number and Apple ID for use with FaceTime and iMessage - Apple Support

Thanks for using Apple Support Communities.
Have a good one