Yes. School-age children generally need suitable school arrangements, and school costs may need to be included when showing enough money for the visa.
If school-age children are included in the Student visa application, school costs may need to be included when showing enough money for the stay.
Some students may have exemptions from certain school fees, depending on their situation. For example, this may apply to children of some PhD students.
For school-age children, evidence of enrolment in an Australian school is usually expected before the visa is decided. Evidence may include a CoE, a school placement letter, or a conditional letter of offer.
Families generally need to keep suitable school arrangements in place while the child is in Australia.