@srichantra Do you want to buy 2018? That is too old. You can only do the last 3 years with Turbo Tax. Online is only good for the current year. You can buy the last 3 years of Turbo Tax here,
https://turbotax.intuit.com/personal-taxes/past-years-products/
You will need a full Windows or Mac to install it on.
For older returns you have to go somewhere else or get the blank forms from the IRS. Here is the link to all the prior year IRS forms
Prior Year Forms and Instructions | Internal Revenue Service
