Filing tax for my high school kids. it shows federal standard deductions only is $5,570. Why it is much lower than 2023 standard deduction of $13,800?

Standard deduction is limited for dependents:

Dependents – If you can be claimed as a dependent by another taxpayer, your standard deduction for 2023 is limited to the greater of: (1) $1,250, or (2) your earned income plus $400 (but the total can't be more than the basic standard deduction for your filing status).