If you’re a iPhone user and don’t have iMessage, there are a few ways to add non-iPhone users to your conversation. The first way is to create an iMessage account for someone else and invite them to join. The second way is to use the “Add User” button in the Messages app on your iPhone. The third way is to use the “iMessage Preferences” option in the Messages app on your computer. The fourth way is the easiest: just type “iMessage” into the address bar of your iPhone and press send.