You’re not signed into iMessage. Open Settings > Messages > Send & Receive, and sign in there.I don't even have the option for "text message forwarding" in settings for messages since the release of iOS17. I just noticed it when I wanted to stop having messages sent to my iPad from my iPhone. Tried everything I could find online to get it to re-appear but nothing has worked. Restoring my phone is the only thing left to try..
I am signed in. Messages are forwarding fine to my Mac and iPad. I just don't have the "text message forwarding" setting anymore. It disappeared. It used to be between "show contact photo" and "send read receipts". I've also signed out and back in and it still doesn't show. I've even signed in and out of iCloud to see if it fixed it and it didn't make a difference. When I search online for any ideas they suggest turning on and off iMessage, signing out and back into iMessage, try reset all settings (not guaranteed fix) and finally restoring the deviceYou’re not signed into iMessage. Open Settings > Messages > Send & Receive, and sign in there.