Home office expenses for employees

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/deductions-credits-expenses/line-22900-other-employment-expenses/work-space-home-expenses.html

As an employee, you may be able to claim certain home office expenses (work-space-in-the-home expenses, office supplies, and certain phone expenses).

This deduction is claimed on your personal income tax return. Deductions reduce the amount of income you pay tax on, so they reduce your overall income tax liability.

It’s line 22900 on your tax form. You can claim a flat rate credit.