Employment Income reported on your T4 slip will be included on Line 10100 in box 14 on your tax return.
"Employment income is all of the money you receive at work through salary, wages, commissions, bonuses, tips, gratuities, and honorarium".
T777 is a Statement of Employment Expenses Form that you'll use to claim any employment expenses. In order to file T777, you must have a T2200 form from your employer certifying that you are eligible for the expenses. The amount you enter on Line 40 of the T777 is the amount shown in Box 14 of your T4 slip, from the employer you are claiming employment expenses and have a signed T2200 form.
CRA (Canada Revenue Agency) provides you the list of eligible expenses that you can claim.
For more clarification, please follow these links:
Line 10100 (formerly 101) on Your Tax Return
Line 10100 – Employment income
If you have any further clarifications, we would be glad to guide you through.