how separate

I suggest having the personal expenses in your personal bank account, and the business expenses in your business bank account.

If there are any personal expenses in your business bank account, those should be treated as draws/distributions.

For any travel for Canada such as airfare,  hotels, internet, communication (cell phone), you can write off those business expenses.

If the business is a S corp or partnership, you'll receive a K-1 that goes on your 1040.

If the business is a sole proprietor LLC, all your business expenses will go on your schedule C of your 1040.

I suggest QuickBooks online for recording of expenses:

https://quickbooks.intuit.com/oa/get-quickbooks/?cid=ppc_G_e_US_.QBO_US_GGL_Brand_Core_Search_Desktop_WP._quickbooks%20online_txt&agid=58700008192086824&infinity=ict2~net~gaw~ar~638827855093~kw~quickbooks%20online~mt~e~cmp~QBO_US_GGL_Brand_Core_Search_Desktop_WP~ag~Core&gad_source=1&gclid=CjwKCAjwr7ayBhAPEiwA6EIGxK9TUPAoirmfdNfiGom9uo9TAKPtdGoFLtSK0nKoC5t7Hmg3iISeKxoCkkEQAvD_BwE&gclsrc=aw.ds 

https://ttlc.intuit.com/community/taxes/discussion/i-want-to-separate-my-personal-taxes-and-my-small-business-taxes-since-i-recently-got-married-how-do/00/578131