You can enter this type of Employment Expense by looking in the lefthand navigation bar for Income > Employment Expenses and follow the steps. Alternatively, you can click the "Find" button in the upper right and type in "employment expenses."
Note: Your husband will need a signed Form T2200 from his employer in order to claim employment expenses.
You do not have to submit this form with the return. However, keep it in case CRA asks to see it.