Flex gives you a centralized way to view, update, and take action on all invoices in your organization. From the Billing section, you can resend invoices, issue credit notes, void or delete invoices, and manually apply payments.
This article explains the available invoice actions, when to use each, and how to handle common scenarios such as duplicates, manual corrections, and unwanted line items.
Before you start
Familiarize yourself with how invoicing works. Get started with invoicing →
Understand what you can do when editing invoices. Edit an invoice →
Available actions
To manage your invoices, go to 
Billing > Invoices. Here, you will see a list of all invoices, which can be filtered by status (paid, overdue, or failed).
Open an invoice to:
Export and download the invoice. Export invoices →
Send the invoice. Click Send to email the invoice to the billing contact. Configure invoice emailing settings →
Void an invoice. Changing an invoice's status to "Voided" excludes it from reports, but it remains in the system. Voiding an invoice preserves its record but makes it non-chargeable and excludes it from financial reports. Items must be detached from the voided invoice before they can be re-invoiced.
Issue a Credit Note. Click Credit Note if you need to return the amount of an existing invoice to its owner. Issue a Credit Note →
Delete an invoice. If an invoice is not paid or credited back, it can be deleted. However, remember that deleting an invoice removes it from the system, and the invoicing number sequence can be disrupted. When you delete an invoice, all associated items automatically become pending, allowing you to re-invoice them. This is useful for correcting errors while permanently removing the invoice from the system.
About sending invoices
Manually sending invoices can be done either for specific individual invoices or in bulk. To send an invoice, select it from the list and click Send to email it to the billing contact.
For bulk sending, select multiple invoices and click Send located in the top-right corner. Attaching relevant documents, such as credit notes, when manually sending invoices is recommended for better transparency.
Read the following articles for more information:
Handle duplicate invoices
Duplicate invoices can disrupt financial accuracy and reporting. Below are the best practices for handling them:
For paid duplicate invoices:
Create a credit note from the duplicate invoice.
Apply the credit note to the customer's future invoices to balance the records.
For unpaid duplicate invoices:
Void the duplicate invoice to preserve an audit trail, as this ensures a record is maintained without affecting financial balances.
Alternatively, you may delete the invoice if no trail is needed, but voiding is generally recommended.
Remove unwanted invoice line items
To exclude unwanted or duplicate billable items from invoices and reports:
Create an invoice for the unwanted item.
Void the invoice. This action excludes the item from invoicing reports, ensuring it no longer appears as billable.