Go to: https://www.altinn.no/en/
Log in with your D-number or Personal Identification Number via MinID or BankID
Click on “Inbox” then scroll down to, “skattetrekksmelding” or "bekreftelse på D-nummer"
Open the “Document” ➡️ Download this to a PDF-file
English: Upload a copy of the document to the Tax Card section in the app