If you require additional support or do not have access to the internet, you can complete the tax check via phone call through HMRC’s customer helpline.
Os oes angen cymorth ychwanegol arnoch neu os nad oes gennych fynediad i'r rhyngrwyd, gallwch gwblhau'r gwiriad treth trwy wneud galwad ffôn trwy linell gymorth CThEM i gwsmeriaid.