You do not file a return if you have no income.
If you're on Social Security, you'll automatically get a stimulus check from the government. Otherwise, if you don't file because you don't make enough money, we just launched a free TurboTax Stimulus Registration product for people like you.
For your protection, do not use this product if you already filed your return or if you plan to file one later this year. One, it cannot update your refund method or bank account if you already filed a 2018 or 2019 return. Two, if you use it now and later file a 2019 return, it'll cause problems with your return. It's only intended for folks not on Social Security who don't file because they're below the filing threshold.