No you don't have to pay for roaming when you travel to US. 

And Yes, you can use data in US. That is included in your plan.

You could find more information about it here https://www.koodomobile.com/en/help/traveling-with-your-canada-us-rate-plan

I am seeing conflicting information. The link you posted indicates that I can call, text, and use data when I am in the USA to numbers either in the USA or Canada. The fine print on the plan indicates that texting from the USA or calling from the USA is not included. Specifically it says calls need to be completed within Canada.

@Steve 

Will you please share a screenshot of the fine print as it appears on your end? (please hide any personal information)

@Flo Koodo 

@Steve 

Thank you for the screenshot! 

This is indeed applicable for the Canada-only plans, however, we can confirm that Canada-US plans include data, calls and text messages Canada/US to Canada/US with no additional fees (there are some exceptions though mentioned in the article shared by @Dinh above).

We will flag this to our dedicated department.

Thank you all.