By default customers will generally be expected to make payment prior to travel.
As a result an Orders status will change to Reserved when the customer says they wish to book but will only change to Confirmed when the first payment is received.

However many businesses have some regular customers where agreements are in place to allow booking without pre-payment and all jobs will be invoiced at the end of the week or month.

To allow a customer to make bookings without pre-payment you must first assign a credit limit to the customer.
Either visit the customers menu and search there or click the customers name on the top line inside any order.
On this page you will have a credit limit box, set your desired limit and this customer will be able to book jobs "On Account" up to this limit.

Once a customer has a credit limit set and balance available a new button "On Account" will appear inside the "Payments" box on their orders.
Pushing this button will confirm the booking and assign it to the account to be invoiced later.

Once a customer has several jobs on account chances are you want to invoice them altogether rather than separately. Inside each order will only allow you to invoice for that order so to raise an invoice with multiple orders you will need to visit the customers page.
Once inside the customer click "On Account" to bring up a list of uninvoiced account jobs. Tick the jobs you want to invoice now and press "Create Invoice"

Since account customers often have a large number of jobs you may want to avoid bombarding them with emails.
Triggered and scheduled emails can be disabled per customer to help with this.

Often an account will have multiple people making bookings that need to be stored and invoiced together.

Each main account/customer record only takes a single email address so the address entered here should be the primary contact.

Additional contacts can be entered into the section "Auto Match Account"
​Any orders with an email matching an entry here will be linked automatically to the primary account, with the different email entered as a contact on the order level.
Entries here can either be full emails (john@example.com) or wildcard matches (*@example.com or *@example.*) to match anything under a certain domain.

Where the main email on the customer record is often or always not the person making the booking you should tick the box "Prefer Contact if Set" in email preferences. This will default to sending emails to the contact on the order, if one exists, rather than the main customers primary email.