Why am I unable to attach a file to an invoice? I could yesterday, but today I cannot.

Hi there, Marsha.

I'm here to help you fix the problem when attaching a file to an invoice. As an alternative, we can upload your file attachment to QuickBooks Attachments lists.

Here's how:

1. Go to the Gear icon and select Attachments.
2. Click the Drag/Drop files here or click the icon box.
3. Upload your file attachment.
4. Look for the attachment in your QuickBooks Attachments lists.
5. On the Action column, click the drop-down menu and select Create Invoice.
6. The created invoice will automatically have an attached file. You can then input the necessary information to invoice your customer.

Moreover, you can also learn how to print or email multiple invoices in QuickBooks Online. 

We're always here to support your business needs. Feel free to leave a comment if you need additional assistance in uploading a file attachment to your invoice.