Single-member LLCs are considered as a disregarded entity by the IRS and they are taxed as a sole proprietorship for federal tax purposes. They can elect to be taxed as either C corporation or S Corporation or continue to remain as a disregarded entity.
Here is how a Single-member LLC files an extension:
Log in to ExpressExtension.
Click Create Business Tax Extension (Form 7004) on the dashboard.
Enter the business details and click Next
Select the Business Entity Type as Limited Liability Company (LLC)
If your LLC is elected to be taxed as Corporation, select Multi-Member/Single Member LLC as a Corporation. Otherwise, you need to file Form 4868.
Select the form to extend (For C Corporation, choose Form 1120 and for S Corporation, choose Form 1120S) and click Next.
Enter the Tax Year and the Tentative Tax and complete the form.
Once filling all the details, review the form, make payment and transmit the extension.