Your single member LLC is a disregarded entity for tax purposes.
You report the income and expenses on Schedule C of your tax return.
If in 2024, there is no income and expenses in the LLC, there is nothing to report and no need for a Schedule C on your return.
However, if the LLC had no income but was active and had business expenses, you can still claim these expenses on Schedule C. This will result in a business loss which can either offset your other income or be carried forward.