If you aren’t signed into Messenger, do so with your phone number (or email address) and Facebook password. You can also open the Facebook Messenger app from within the Facebook app by tapping the icon that resembles a speech bubble with a lightning bolt in the upper-right corner.
If Messenger opened to a conversation, first tap the “Back” button in the top-left corner of the screen.
On iPhone, this icon will display your Facebook profile picture if you have one.
If you don’t see this option appear, your typed-in username isn’t available.
If you aren’t logged into Facebook, enter your email address (or phone number) and password before proceeding.
If you don’t see this option, make sure you’re viewing the General page by clicking General in the upper-left corner of the page.
If this button is grey instead of blue, your typed-in username is already taken.
