I created an LLC in N.C. last year but did not open a bank account or create any business activity. Am I required to file and what form would I use?

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:

What Is a Schedule C IRS form?

What is Form 1065, U.S. Return of Partnership Income?

S-Corp Federal Tax Filing Dates