Where does a FT university student report income from casual employment when no deductions (tax, ei, cpp) have been taken of their pay?

Line 104 is the appropriate line to report these casual earnings.  These earnings are not subject to EI or CPP. However with regard to CPP, she can elect to pay CPP on these earnings.  If she chooses to do so, TurboTax will automatically calculate the amount.  If she chooses not to, no amount will be calculated or assessed.  You should also be aware that these earnings are eligible for the Canada Employment Amount of up to $1,146 which is a non-refundable credit.  TurboTax will automatically calculate this amount.  For more info, please see http://www.cra-arc.gc.ca/tx/ndvdls/tpcs/ncm-tx/rtrn/cmpltng/rprtng-ncm/lns101-170/104/ntrprtd-eng.ht...

You can also consider any expenses incurred while earning the casual income.  You do need to keep a record of the revenue and expenses (including receipts and/or documentation) but you can report the net at line 104.  

If the amount is greater than $3500, then you should report it as self employed income, as CRA will be looking for the CPP remittance.

last year Turbo Tax did not calculate this CPP amount as payable and sent us a reassessment notice, costing us an additional $1000 plus interest! Why is this not automatic note on the forms?

a_waz: What? That makes no sense. On casual income, these earnings are not subject to CPP or EI. If the amount is greater than $3,500, and you reported it as self-employment income, then you are simply being taxed at the appropriate average rate based on whatever the total income was, less allowable deductions. It is not a "CPP amount" that is payable, it is a "tax on income after allowable deductions amount". The thing with self-employment income is that there is no tax deducted at source the way there is with employment income. So people who have significant amounts of self-employment income, while that's awesome, and you may also have deductions not available to the typical T4 employee, you will also need to have the self discipline as a "self-employed" business person to set aside enough savings to cover that potential tax liability that, for the T4 employee, their employer "sets aside" and remits for them.

To clarify, my original comment of October 29, 2019 was directed to a_waz, regarding casual self-employment income.

The OP (original post) by thornhillrc with regard to his daughter's casual employment, IMO, does not qualify as self-employment income, it sounds more like casual employment, so as others have indicated, line 104 is the appropriate place to declare this income, although I am surprised the employer did not issue a T4 (even though it sounds like no tax or CPP or EI contributions or other deductions were withheld). Does anyone know off hand what the income threshold is before the CRA requires the employer to issue a T4?

In my case, both of my sons had casual employment while attending university, and we always got T4s from the employers, even when no deductions were made due to small amounts of income from one or more of those employers.

Self-employment status does not typically apply in most cases for this type of casual employment. Check here at the CRA website for the guidelines to consider to make this determination: https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/rc4110.html

To clarify, you should only report income as self-employment income if that income qualifies to be considered as income from self-employment. The dollar amount is not what is relevant, it is the terms of the agreement.

Guidelines here:
https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/rc4110.html