Why should I file my US tax return?
Under US tax law, non-residents who have worked in the United States are required to file their US income tax returns.
The presentation of the declaration is not obligatory only in cases where:
you did not earn any income in the United States during the fiscal year or
your income did not exceed $ 4,000
However, it would be in your interest to produce the income statement even if your earnings did not exceed $ 4,000. Why? Because you can recover the taxes withheld by the US authorities.