Your default profile (your name and image) is used by default when inviting a new contact or accepting a contact’s invitation.
Tap on your profile image at the top corner of any twinme home screen to display the “Settings” menu tab. Tap again on your profile image and on the “Pencil” icon to edit it. You can then modify the image and/or the name and/or the description (about) of your default invitation profile. Changes become effective after tapping on “Save”.
You may decide to propagate the change to your contacts, or not.