My company is a US Delaware C Corp. I want my app to be available in Canada as well as US. If I plan to introduce a subscription service, do I have to file income tax in Canada as well? I know Apple collects and pays Sales Taxes for us. I would think since Apple pays us in the US, I would only need to care about US taxes. Is this correct?

I have an app that only allows for LinkedIn, Google, and Apple Sign In. There is no way to register with phone or email. Can I submit a Sandbox account for App Review?