These settings can be changed via Settings > System Defaults.
Your accounting default values will be used on accounting-relevant areas of the system.
Accounting Method: the method of which your company operates (either as cash basis, accruals or none).
Default GST on invoices: whether you would prefer to use inclusive or exclusive GST on invoices by default. This can be overridden when creating a new invoice.
Default Invoice Due Date: Default due date when creating new invoices. This can be overridden when creating a new invoice
Preferred Payment Method: Your preferred payment method for invoices (bank account, credit card or none). By selecting a default payment method, your generated invoice PDF will say (preferred) next to your preferred payment method.
Bank Account Details: Bank account details which will be printed on the invoice PDF. A bank account is optional and you can instead accept direct card payments using a payment provider.
If you choose to display bank account details, you can also set your own terms and conditions which will be printed onto the invoice PDF.