Thanks for sharing your concern here in the Community, @PJD007.
As Simple Start does not have a bills feature you can only enter expenses. Which are already paid. If you want to account for purchase invoices yet to be paid you may want to look at upgrading your subscription plan(to Essentials or Plus).
You could look at doing a journal entry to record the expense account category and the creditor owed. As an alternative but we'd advice speaking with an accountant if you're unsure on the journal entry.
Feel welcome to visit us again with any concerns you may have. The Community always has your back.
