Create Invoice AttachmentSQUARE_CREATE_INVOICE_ATTACHMENT
Upload and attach a file to a Square invoice. Use this action to add supplementary documents (receipts, contracts, supporting documentation) to an existing invoice. Attachments can only be added to invoices in DRAFT, SCHEDULED, UNPAID, or PARTIALLY_PAID state. Square supports up to 10 attachments per invoice with a combined maximum size of 25 MB in production (1 KB in Sandbox). Supported file formats: GIF, JPEG, PNG, TIFF, BMP, PDF. Creating an attachment increments the invoice version and triggers an invoice.updated webhook event.