Hmm.. Can you tell me which phone that is? I'm also using a phone from 2017 and that's how it's done there but I just realized I was using Google's Messages app.

Thanks for you reply.

unfortunately, when I tap on the message, at the top it says ‘ one selected’ and on the upper right there are two boxes one superimposed on the other.  There are not 3 dots.

when I go one sceeen back, there are 3 dots but they reveal choices such as: insert smiley, delete thread etc ...everything but forward!    I got the phone in 2017 so perhaps it did not have that feature added then.

still a puzzle.  

Hi Patricia. Tap and hold on the message you want to forward -> Once the message is highlighted, tap the 3 dotted menu on the upper right side of the screen -> tap forward.