It depends on the way that the LLC was set up. LLCs can be set up as a Sole proprietorship, a partnership, or an S-Corp.
- If the business is a Sole proprietorship, you will need a Schedule C. This'll be included in your personal tax return. In this case, if you didn't have any business activity, you don't need to include anything for your business.
- If the business is a partnership, you will need to complete a Form 1065. The business will complete a separate return, and will issue any partners a Schedule K-1 to include on their return. In this case, if you didn't have any income or expenses from your business, you don't need to complete a return.
- If the business is an S-Cor, you will need to complete a Form 1120-S. It'll also be a separate return from, the business will issue Schedules K-1 to any members. If your LLC is set up this way, you will need to file a return, even if you didn't have any income or expenses.
For more information refer to the following TurboTax help articles: