You can buy TurboTax, but as with all tax software, you need a copy of the application to read / modify (file an amended return) the files. Since OS upgrades eventually will mean the version you bought to file TY 20xx taxes will stop working due to incompatibility, you are stuck buying new versions.
I use StudioTax (free download, MacOS, WindowsOS, Canada only) which has no restrictions except limited to 20 returns. Any return no matter how simple or complex can be used, every schedule and form included, and it's eFile Certified so you can file electronically, takes about 2 minutes. Will print (pdf) of your entire return and attachments so you can always read the return in the future, and has modest installation requirements so works with any version of an OS you are likely to have installed.
Why free? They earn their income from commercial tax preparation firms, individuals who do their own taxes aren't customers of either StudioTax or their clients.
There are other free return softwares available, but StudioTax resides on your computer so you have control of the data. uFile (for example) requires you to file online. Not for me; tax return data is too important to upload to the internet. eFile to Canada Customs and Revenue Agency is encrypted.