This is because Adobe does not provide direct links to older versions of its software on its website. If you are looking for a specific version of Adobe Illustrator, such as Adobe Illustrator CC 2017 19.0.0 (64-bit), you may have a hard time finding it online. After your free trial ends, your Creative Cloud membership will continue, unless you cancel it before the free trial ends. You will need to sign in or set up your Adobe ID and download the Creative Cloud desktop app to install the software. If you want to try Adobe Illustrator for free, you can download a 7-day free trial from the official website.