You cannot use a standard "Chatpad" (mini-keyboard attachment) on Xbox 360. The Xbox 360 controller lacks the proprietary data port (found on Xbox One/Series controllers) required for the official Chatpad.
Works natively on newer controllers (3.5mm port or dedicated connector). Types directly into any text field. Not backward compatible with 360.
Summary: For 360: USB Keyboard for dashboard typing, Headset for voice. No chatpad hardware support.