When you purchase one of the TurboTax desktop editions to install on a personal computer you install the software purchased on up to 5 computers that you own.
Additionally, the software purchased allows you to e-file 5 federal tax returns at no charge. Any federal tax returns over 5 have to be printed and mailed. If you are completing state tax returns there is an e-file charge of $25 for each state return e-filed. This charge can be avoided by printing and mailing the state tax return.
You can install Turbo Tax on 5 computers you own. Are you in Canada? This is for the USA program.
Since you now have to log into an Intuit Account when you first install it, all your downloads and licenses are listed there (even if you bought it from somewhere else) so if you need to install it again or install on another computer, even on the other operating system (Windows, Mac) you can download it again.
Access your downloads here
https://shop.turbotax.intuit.com/commerce/account/secure/login.jsp?pagecontext=download
If you use the Online browser version it is only good for 1 return per account. You can use the same email address for 5 accounts. You would pay for each return.