Your preferred name is the name (sort of like a nickname) that displays on your account in places like your MyMobile greeting. It's different than your legal name; it's what you like to be called in your daily life.
To change your preferred name, simply sign in to MyMobile, click on My Account, and choose Personal info. Click the pencil icon next to "Preferred name" to edit your name.
Please note: You cannot use profane or inappropriate language as your preferred name.