If you are self employed and use your home to conduct business, it is your principal place of business and you use the space to earn business income, a portion of your monthly rent can be deducted from your taxes. 

If you use part of your home for both your business and personal living, calculate how many hours in the day you use the rooms for your business, and then divide that amount by 24 hours. Multiply the result by the business part of your total home expenses. This will give you the household cost you can deduct. If you run the business for only part of the week or year, reduce your claim accordingly.

For more information visit - https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/sole-proprietorships-partners...