Good day, I have seen many solutions, mine is not the best, but it is most accurate with CRA requirements.

1. Enter the client name as stated on their SIN, first name and last name (ignore middle or second name on the SIN).

2. Select check mark to indicate first time filer; this will activate the middle name field.

3. Now, enter the middle name or second name in this field.

Do not file an income tax with the first or last name field blank, that is not correct process even if it works; you or the client may have difficulty with CRA later.