2018 isn't available now, how do i start the return?

The 2018 tax filing season officially ended on Oct 15, 2019. So the online version of TurboTax for the 2018 tax filing season is shut down permanently and forever so they can prepare for the 2019 tax filing season.

If you need to prepare and file a 2018 return then you have to download the CD software and physically install it on your Windows or MAC computer. Then used the installed program to prepare your 2018 tax return. You can purchase TurboTax 2018 at https://turbotax.intuit.com/personal-taxes/past-years-products/

Note also that the IRS has closed e-filing for the 2018 tax filing season so they can prepare their computers for the 2019 tax season also. Therefore, when you complete your 2018 return using the Cd/Desktop version of the program you will have to print, sign and mail it to the IRS.

If you will also be filing a state return, then the same rules apply for your state return.