Supplier invoices arrive in all sorts of ways: attached to an email, as a download link, inside a customer portal… and at the end of the quarter you have to hunt them down one by one. This article suggests a simple workflow, using tools you probably already have, so they practically sort themselves.
The goal
Every invoice should end up in one place, with a file name that says what it is, and logged in a spreadsheet that’s ready for the quarter. No expensive software and no relying on memory.
Step 1: an email filter
Almost every email service lets you create rules. The idea is for messages with invoices to be labelled or moved to an “Invoices” folder automatically.
- Filter by sender: your usual suppliers’ addresses.
- Filter by words in the subject: “invoice”, “factura”, “receipt”.
- Filter messages with PDF attachments.
It doesn’t have to be perfect from day one: every time an invoice slips through, add that sender to the filter.
Step 2: one folder and consistent file names
Store the PDFs in a folder per year and quarter, for example Invoices/2026/Q3, and rename each file with the same pattern:
YYYY-MM-DD_supplier_amount.pdf → 2026-09-14_electricity_58.20.pdf
With this format, files sort themselves by date and you can find any invoice without opening it.
Step 3: let them save themselves
This is where the actual automation comes in. There are several options depending on the tools you use:
- Google (Gmail and Drive): a small Google Apps Script can check the “Invoices” label, save the attachments to Drive and mark the email as processed.
- Microsoft 365 (Outlook and OneDrive): Power Automate has ready-made templates to save email attachments to OneDrive.
- Integration services such as Make or Zapier do the same with many providers, in exchange for a subscription beyond a certain volume.
Automatic renaming is the trickiest part, because the amount and the date are inside the PDF. A middle ground: have the automation save the file with the sender’s name and the email’s date, and fill in the amount yourself when you review it.
Step 4: the spreadsheet
A simple sheet using the same rules for every invoice, with these columns:
- Date
- Supplier
- Description
- Taxable amount
- VAT
- Total
- Link to the PDF
If the previous step saves the files to the cloud, the automation can add a row for each new file, with the date, supplier and link. You only fill in the amounts. At the end of the quarter, a pivot table gives you the totals by supplier and VAT rate.
What not to automate
- The review: glance at each invoice before accepting it. An automation will happily save wrong invoices too.
- Paper invoices: scan them with your phone and save them in the same folder with the same naming. Order is what matters.
- Sensitive data: if you use external automation services, check what data goes through them and where it’s stored.
Backups
If your invoices live in one place, that place needs protecting. The classic rule is 3-2-1: three copies, on two different types of storage, with one of them away from your home or office. Remember that invoices must be kept for years: in Spain, at least four for tax purposes (the limitation period) and six under the Commercial Code.
In short
An email filter, a single folder, consistent names and a spreadsheet. With that, closing the quarter goes from a treasure hunt to a calm review. The rest is fine-tuning.