How can I preview and send an invoice?

Use "Billing" to see all the invoices you created in Groobix.
On this page, you can click on the envelope icon at the right of each invoice, to preview it.

In the preview page, you can see the invoice as it will be received by your customer.

To send it, just enter the email address you want to send it to, at the bottom of the page. In this field, you will be presented with a default email address, extracted from the customer's data in your Groobix database.

You can change the email address and send it to anybody else, for instance, you can send it to yourself to try it out!