Go to Settings → Integrations and enter your Stripe API keys. Once connected, any invoice will show a "Pay Online" button for your clients.
Yes — go to Profile Settings. You can choose AUD, USD, GBP, EUR, or NZD and set your tax label (GST/VAT/Sales Tax) and rate.
Invoices are automatically flagged as Overdue once past their due date. You will see alerts on your dashboard. Email reminders can be configured to auto-send at 7, 14, and 30 days via Settings.
Yes. Cancel at any time from Billing → Pricing. Your access continues until the end of the billing period and you will never be charged again.