QuickBooks Online has default liability accounts for superannuation, thomas-higg.
However, we recommend checking with your accountant if you can use them for self-employed individuals. These accounts are posted under the Payroll Liabilities or normally used if you're using payroll in QBO.
If you're using QuickBooks Self-Employed, check this link on how to handle self-employed super contributions in your account: https://quickbooks.intuit.com/au/resources/self-employment-tax/super-tax-self-employed/.
The Community is always here if you have other questions.