The key difference lies in who is taking responsibility for the loan.
When you co-sign, both parent and student are responsible for the loan. Co-signing may help your student qualify for a lower rate and may help their chances of approval since they typically don’t have much of a credit history.
For a parent student loan, the parent/guardian takes full responsibility. A parent loan will have no impact on your student’s credit and can also help reduce the debt burden on students.