Invoices are built from completed, unbilled visits on a customer's or community's page and emailed as a PDF on your letterhead from your company name. Statuses: draft, sent, paid, overdue, void. Money is stored in integer cents.
Residential customers can be billed monthly in advance, monthly in arrears or per visit, and Unqio can create and send those invoices on its own. The Billing article explains each mode.
With Stripe connected (Settings → Payments), each customer gets a card-on-file link and a portal. Autopay charges the card on file within the hour of an invoice being sent and retries a failed card three times over a week. The customer can update their card from their portal at any time.
QuickBooks Online (Settings → QuickBooks) receives sent invoices and returns payments; commission and technician pay can be written as checks.