To keep this as simple as possible, it’s best to treat all foreign income the same way as you would handle the income earned from a Canadian company.
Really the only difference here is if you are paid in a foreign currency and have to deal with the exchange rates. In that case, the Canadian Revenue Agency recommends you to use the Bank of Canada exchange rate that was in effect on the day you were paid, or use the average annual exchange rate. For more information on filing your taxes, it’s best to check the Canadian government website. As well, depending on what country your company or employer is based out of, you may have to pay their taxes as well, so it’s best to check their government website or ask an accountant.