Hi,
For 2021 and later:
-T3 Return electronic filing is E-filing: a CRA issued e-file number and password are required
- T3 Slip filing is XML transfer, requiring a transmitter number, Business/ Trust account number and matching Web Access Code, (WAC). All three of these are issued by CRA.
Entries for business number and WAC entered in Efile > Options do not populate the CRA XML server log in screen. Manual entry is required
More information can be found in a ProFile Community article here
