Re: "problems with sharing texts between group project participants"
Just try to touch and hold the message you want to forward,
and
voila : the menu with (...) "More" should appear.
More info: Forward and share messages on iPhone - Apple Support
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If that is not working for you:
Try restarting your iPhone, and check whether that process restores order
If needed: See how to: Restart your iPhone – Apple Support
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If still in need of help:
Let Apple know:
Either through support contact options : (eg: online chat / phone / email etc.)
eg: Scroll to the bottom on their Messages support website:
Messages for iPhone, iPad, Apple Watch, and Mac - Official Apple Support
or
Apple Phone Numbers around the world:
(ie: scroll to "Contact Live Support" to choose your country):
Contact Apple Support - Apple Support
or
by sending feedback: Web-form: Feedback - Messages - Apple