In general, an LLC with no revenue and no deductions or credits doesn’t need to file an IRS return. That’s true of LLCs taxed as sole proprietorships and as partnerships, but not for people who have elected to have their LLC taxed as a corporation. Corporations must file regardless of activity.
Here’s a few places to start: https://www.irs.gov/faqs/small-business-self-employed-other-..., https://ttlc.intuit.com/community/business-taxes/discussion/...