If I immigrated to the USA in July 2018, I need to file my taxes, how and where do I do that?

I was single in all my time in Canada in 2018, but married in August 2018, after immigrating. I can't find how to file them from another country.

Troubleshooting

Since you have immigrated to the US, you'll submit a paper copy of your return rather than using NETFILE.

https://turbotax.community.intuit.ca/replies/2648070