Can I save my 2017 tax return as a PDF?
Yes, you can. These links will provide you steps on how to do this, depending on which version of TurboTax you are using.
It's also a great idea to save it as a tax data file as well. And for steps to do that, go here Save a Backup Copy of Your Tax File
This link What's the difference between the tax data file and the PDF file? explains the differences.