A T4 statement is an information slip prepared by your employer with information you need to complete your annual income tax return. It lists things like wages your employer paid you, and how much they took from your pay for Employment Insurance, income tax, and Canada Pension Plan.
When an employer fires you or lays you off, they usually have to give you notice ahead of time. The amount of time can depend on many things including how long you’ve been in the job.
If they let you go right away, they must pay you the money you’d have earned if they had told you ahead of time. This is called pay in lieu of notice or termination pay.