Thank you for your question.
Before claiming any work-related expenses, you must have a completed Form T2200 Declaration of Conditions of Employment signed by your employer.
https://turbotax.intuit.ca/tips/what-expenses-can-you-deduct-as-an-employee-5429
As per CRA:
Form T2200, Declaration of Conditions of Employment, is a form your employer fills out to certify you were required to pay for your own employment expenses. Form T2200 is kept by you and is not included with your tax return.
Form T2200S, Declaration of Conditions of Employment for Working at Home Due to COVID-19, is a shorter version of Form T2200 that you get your employer to complete and sign if you worked from home in 2020 due to the COVID-19 pandemic and are not using the temporary flat rate method. Your employer completes and signs this form to certify that you worked from home in 2020 due to COVID-19 and had to pay your own home office expenses. Form T2200S is kept by you and is not included with your tax return.
Form T2200 and Form T2200S must be signed by your employer. It is up to your employer to determine who is authorized to sign these forms.
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