Biller Genie can attach files to outbound invoice reminder emails so your customers receive supporting documents along with the invoice. There are three ways it happens: (1) the invoice PDF itself attached automatically, (2) QuickBooks Online attachments synced and attached automatically, and (3) one-off files attached manually when you send an immediate reminder. This article covers all three plus what to do when you need attachments to stay permanently on the invoice record.
Files attached to your QuickBooks Online invoice automatically ride along
If you use QuickBooks Online, Biller Genie automatically syncs invoice attachments from QBO and includes them on outbound reminder emails. When you attach a supporting document (PDF, image, etc.) to an invoice in QBO and check the "Include on Send" option on that attachment, Biller Genie pulls it during the next sync and includes it on every reminder we send for that invoice.
The "Include on Send" flag is the on-switch
Biller Genie only pulls attachments that have the QBO "Include on Send" flag turned on. If you've attached a file to the invoice in QBO but Biller Genie isn't including it on reminders, that flag is the first thing to check. In the QBO invoice view, find the attachment row, click the dropdown, and toggle "Include on Send" on. Save. The next Biller Genie sync picks it up.
The Biller Genie-side toggle
Whether Biller Genie includes the synced QBO attachments on outbound reminders is controlled by the Show Attachments to Reminders setting in Control Panel > Invoice Defaults. When this toggle is on (the default for most accounts), QBO-synced attachments ride along with every reminder. When it's off, Biller Genie still syncs the attachments but doesn't include them in outbound emails.
Total size limit: ~14.5 MB
Email providers cap how big an outbound email can be. Biller Genie's email service (Mailjet) enforces about 14.5 MB total per outbound email — that's the combined size of all attachments together. If the QBO attachments on an invoice add up to more than that, Biller Genie skips attaching them and sends the reminder without files (the reminder still goes out; just without the attachments). If you're seeing attachments missing from reminders for one specific invoice, check the total attachment size in QBO.
QuickBooks Desktop and Xero: no automatic attachment sync
QBO is the only accounting software that Biller Genie pulls invoice attachments from. If you use QuickBooks Desktop or Xero, attachments stored on invoices in those systems are NOT synced into Biller Genie or included on reminders. Use one of the manual paths below if you need files on outbound reminders for those merchants. For more on the QBO integration, see How to Connect QuickBooks Online.
Auto-attaching the invoice PDF
Separately from the QBO attachment sync, Biller Genie can also attach the invoice PDF itself to every reminder. Turn on Send Reminder With Attachment in Control Panel > Invoice Defaults. With this on, every outbound reminder gets a fresh copy of the current invoice as a PDF — no manual work, no syncing from QBO, just the Biller-Genie-generated invoice rendered as a PDF. Useful if your customers want a printable copy in the email rather than relying on the Pay Now link.
Attaching a file when sending a manual / immediate reminder
The Send Reminder Now flow on an invoice (also called "Immediate Reminder" / "Send Invoice Manually") includes an attachment field. Files attached here are sent with that one specific reminder only — they're not stored on the invoice for future reminders.
- Open the invoice from Invoices > All Invoices.
- Click Send Reminder Now (or Send Invoice, depending on the variant).
- Use the file picker in the dialog to attach one or more files.
- Optionally adjust the recipient list (To and CC), then click Send.
Supported file types and per-file size
- Max size per file: 5 MB.
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Allowed extensions:
pdf,doc,docx,txt,xls,xlsx,jpg,png. - You can attach multiple files to a single reminder, subject to the per-file size and total ~14.5 MB email size limit.
The recommended pattern
For QBO merchants, the cleanest workflow is:
- Attach the supporting document to the invoice in QuickBooks Online (it's the source of truth for the invoice anyway).
- Make sure "Include on Send" is checked on each attachment you want emailed.
- Make sure "Show Attachments to Reminders" is on in Biller Genie's Invoice Defaults.
- Every scheduled reminder Biller Genie sends will now include those attachments automatically. You never have to manually attach again for that invoice.
For QBD or Xero merchants (which don't have automatic attachment sync), use the manual Send Reminder Now attach for each send, or put a link to a shared file (Google Drive, Dropbox) in the invoice memo so the link appears on the invoice PDF itself.
What about the customer portal?
Attachments are an email-send-time feature in Biller Genie — they ride along with reminder emails. They are not shown on the invoice page inside the customer portal. If your customer logs into the portal directly (rather than clicking a Pay Now link from an email), they won't see the attached files. For documents the customer needs to access on demand, host them somewhere accessible and link to them from the invoice memo.