What kind of income does she have? W2 or 1099NEC? How much is the earned income? Only wages and self employment count, not interest or dividends.
The Standard Deduction for an individual for whom an exemption can be claimed on another person's tax return is limited to the greater of:
…..$1,100 or
…..Your earned income for the year + $350 (but not more than 12,400 2021)
So you would get a minimum of $1,100.
See Table 8 Standard Deduction worksheet for Dependents on Page 25
https://www.irs.gov/pub/irs-pdf/p501.pdf
Or the 1040 worksheet on page 32
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
if it is self employment income on Schedule C you have to first deduct 1/2 of the self employment tax.
