I do not have an Add Contact button -- only a Hide button

I cannot find the add contact in order to add another contact to a group text message already started. I’ve tried for a week and have restarted the text 3 times to add someone when I finally had their number. I’ve followed the info given here, but when I click on info there is not an add contact choice. Thanks!

do they have an iphone? if they dont have an iphone you wont be able to add them

I don’t know if they do or not... there isn’t an add button to try. Will the add button only show up if they have an iPhone?