What are the tax implications for individuals on an H1B visa filing their taxes using form 1040 or 1040NR?

Individuals on an H1B visa must file their taxes using either form 1040 or 1040NR. The tax implications depend on their residency status for tax purposes. If they are considered a resident for tax purposes, they will file using form 1040 and report worldwide income. If they are considered a nonresident for tax purposes, they will file using form 1040NR and only report income from U.S. sources. It's important to determine residency status to ensure proper tax filing.