How do I text multiple phone numbers at once?

You can text multiple people by tapping the writing icon in the upper right hand corner on the main screen of the Messages app. From here you can start typing the names of the contacts you want to add, or add any phone number. You can use a comma to separate each contact name or phone number to add multiple people to the list or group. The app will autocomplete any contacts you have stored in your phone when you begin typing a name.