Is it possible to send an invoice to the customer other than through Zoho FSM?
Yes, you can download the invoice from Zoho FSM, send it to your customer, and then mark it as sent in Zoho FSM.
Downloading an Invoice in Zoho FSM
- Open the invoice.
- From the Send Invoice dropdown, select Download.

The invoice will be downloaded in PDF.
Marking an Invoice Sent in Zoho FSM
- Open the invoice.
- From the Send Invoice dropdown, click Mark as Sent.

This option is available only when the invoice is in the Draft state.