How does a student report cash income ?

Is it for work or jobs you did?  That is self employment income.

You can enter Self Employment Income into Online Deluxe or Premier but if you have any expenses you will have to upgrade to the Self Employed version or use any of the Desktop CD/Download programs.

How to enter self employment income

https://ttlc.intuit.com/community/self-employed/help/how-do-i-report-income-from-self-employment/00/26653

You don't need to get a 1099NEC or 1099Misc or 1099K.  Even if you did you can enter all your income as Cash.  Only the total goes to schedule C.

It depends on the source of the income. Excess scholarship money is reported differently from money received for working. 

The IRS generally considers undocumented cash income (no W-2 or 1099-NEC), for work performed, to be self employment income. You report the income from your own records. Enter at "Business Income & Expenses" and TurboTax (TT) will complete Schedule C for you and allow you to deduct any expenses associated with this income. You'll also have to pay self employment tax (social security & medicare tax) on any profits greater than $432.

There is a "one time gig" exception to reporting cash as self employment income, depending on the details of what you did, whether you have done it in the past and/or plan to do it again.  Then it can be entered as other income.