Your employer needs to fill out and give you a copy of the T2200 Conditions of Employment – https://www.canada.ca/content/dam/cra-arc/formspubs/pbg/t2200/t2200-fill-15e.pdf
Once you have the form, then you need to fill out the Worksheet for Employment Expenses – https://bptax.ca/wp-content/uploads/2017/07/1.c.WORKSHEET-EMPLOYMENT-EXPENSES-T2200-1.pdf
We will then take that information and claim the expenses on your personal tax return.