Hi @zospiegs,
Sorry to hear you don't have your T4 - even if you don’t have all your tax slips, we encourage you to file by the deadline to avoid penalties and interest. You can use your pay stubs or statements to estimate income and calculate any related deductions and credits you can claim. You should keep a copy of all those documents in case we ask to see them later. You can check out the CRA website for more guidance in respect to this: https://www.canada.ca/en/revenue-agency/news/newsroom/tax-tips/tax-filing-season-media-kit/tax-quest...
