I am a non-resident and my source of income in Canada is only from my investments in a monthly income fund. What forms do I need to fill up for filing my tax return?

Thanks for your question. You'll need to declare your Canadian investments. The TurboTax software will ask you questions about your 2017 Canadian investments so you can fill out your return correctly. Click on the "Find" button in the top right corner and type in "Investments", you'll then be guided accordingly.