@freddens , I am not able to answer without more information such as
(a) Are you a US Person ( citizen / GreenCard holder ) moved to Denmark ?
(b) If you are not a US person, then were you in the USA on work visa or what ? When did you enter and when did you leave ?
(c) Are you married and if so to whom ( US person or a foreign person ) ?
(d) Are you talking about tax year 2022 or 2023 ? How did you file 2022 ?
Generally for a US person there is no special filing requirement when leaving the US ---- one files just as before , except that one is still taxed on world income and returns are still on 1040. For Non-US person there are some specific requitements.
I will circle back once I hear from you
