If this is a single-member LLC (you are the sole owner), then you will file the information for that LLC on your personal income tax return using Schedule C (Self-employed profit and loss).

If the LLC is owned by more than one person, it will most likely need to file a partnership income tax return (Form 1065) UNLESS there was an election made to be taxed as a C corporation or a subchapter-S corporation, in which case it will need to file Form 1120 (C corp) or 1120-S (S corp).

NOTE:  A single-member LLC may make the election to be taxed as a corporation.