Elias here with Shopify Support. Thank you for reaching out.
I understand you set up a CAD bank account and your store sells in both USD and CAD. If you’re using Shopify Payments, you can sell in multiple currencies and have the payout converted to the currency of your bank account. That said, you can only add one bank account. If you want to get paid in CAD, then you can connect your CAD bank account. Or, if you want to get paid in USD, you can connect your USD bank account.
We have a guide to help you with enabling your store to sell in multiple currencies. If you’re selling and getting paid in different currencies, you can take a look here for our supported currencies and conversion fees.
I hope this helps clarify the selling in multiple currencies. If you have any other questions on this topic, don’t hesitate to let me know!