19 year old ds1 just messaged me from uni saying his new job needs a letter from hmrc with his NI number on so they can pay him. I can't find anything. I've got loads from the dwp but none from HMRC. Google tells me letters from HMRC are rare because they are mostly paperless. Does anyone know what HMRC would write to him about as it might give me ideas of where to find something from them.