If you are the sole owner of the business *AND* did not file IRS Form 2553 or 8832 to have your business treated like a corporation for tax purposes, then keep reading. If that first statement is not true, stop reading and let your readers know.
A sole proprietorship or single member LLC is considered a disregarded entity by the IRS. All business income/expenses is reported on SCH C as a physical part of your personal 1040 tax return. Doesn't matter if you file a joint return either.
You must complete the returns in order, starting with the oldest tax return first. The online version of TurboTax can only be used for the current tax filing year, which at this time is 2019. To complete a prior year return you must purchase and install the CD version of the program on your computer.
You can purchase TurboTax 2017 and 2018 (two physically separate purchases) at https://turbotax.intuit.com/personal-taxes/past-years-products/ *MAKE* *SURE* you are under the correct tab for the tax year to be purchased. Once you buy it, you own it.
After you pay for the CD version of the program you can download the CD installation file immediately. Then double click the downloaded file to install it on your WIndows or MAC computer. PAY ATTENTION to detail and ensure you buy the correct version for your operating system. If you have a MAC and you purchase the Windows version, then you own it.
Once the program is installed you can double-click the "TurboTax 2017" icon on your desktop to start the program and get started on your 2017 tax return. Once you have completed the 2017 return in it's entirety, then you can install TurboTax 2018 and get started on your 2018 tax return.
NOTE: you *CAN* *NOT* e-file a prior year tax return. The IRS says so. You have to print it, sign it and mail it yourself to the IRS. The same applies if you are required to file a state return also.
Per the IRS, you have to mail each individual tax return in a physically separate envelope.
