Where do I enter the income tax due and paid on my US return on my Canadian tax return?

For the downloaded version of the software, please see screenshot attached to show you where to enter in your taxes paid on your Canadian tax return.

This will appear after you have completed the Profile section of your tax return.

Tried that but it didn't work. Entered source country USA, exchange rate 1.2970 (IRS 2018 average) and foreign tax paid $2,500 but tax owing amount doesn't change.

Please view link below From TurboTax to have a better understanding of this credit and determining your eligibility:

Canada’s Foreign Income Tax Credit
https://turbotax.intuit.ca/tips/canadas-foreign-income-tax-credit-6223

And this one for further clarity:

How do I report foreign income, pension, and other foreign amounts?
https://turbotax.community.intuit.ca/replies/2647976

The first link just tells me a tax treaty exists between the U.S. and Canada but doesn't tell how to enter this in TurboTax. The second link is related to income not foreign tax paid.

The image shows you were to enter in your foreign tax paid.  If you have any other concerns, you may want to get on the phone with one of our support agents to assist you personally, Here is the link:

I want to talk to someone. How do I phone you?
https://turbotax.community.intuit.ca/replies/3152013