As long as it remains a single-member LLC you don't file separately for it. You include it as business income in your personal tax return. That's all you have to do.
If it becomes a multi-member LLC it gets a lot more complicated. You have to file a separate partnership tax return, Form 1065, for the multi-member LLC. The partnership tax return includes a form called Schedule K-1 for each partner with information that the partner has to enter in his or her personal tax return. There may also be issues about how you and the other partners are paid. This is why I strongly suggest that you obtain local professional help if you make it a multi-member LLC.
