You can delete the login you created for the JFTT Workforce app from inside the app.
The app signs you out, disables that login, and removes your profile name and phone. You cannot sign in with that account afterwards.
Invoices, credit notes, payments, quotations, time entries, expenses, and photos stay with the business. Those records can be required for accounting. Deletion does not remove another member's records.
Give another member the owner role first. The app will not delete the only owner of a business.
If you cannot sign in, email JFTT at joeyfeirtear@gmail.com. That address is the working contact until support@jftt.ie is active.