This post is meant as a starting point for Employers, also suggest to review the CRA web & call CRA with further questions.
Employer is responsible for both T4 & T4 SUMMARY each year & provide T4 to employee.
https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/payroll/completing-filing-information-returns/t4-information-employers/t4-slip.html
https://www.canada.ca/en/revenue-agency/services/forms-publications/forms/t4.html
T4 Summary = total of ALL remittances paid to ALL employees. This is required even if just one employee
whereas T4 shows ONLY the employee deductions (amounts)
* eg the CPP amount is only for the employee portion (not employer portion)
EI https://www.canada.ca/en/revenue-agency/services/forms-publications/forms/t4.html
* PLEASE be advised we are NOT bookkeepers or accountants – please talk to CRA or an accountant for assistance.