How to send an invoice as a PDF

An invoice only helps you once your client can open it, read it and pay it. A PDF is the usual way to send one, because it looks the same on every phone and computer. A few small things still go wrong again and again: the wrong file type, a name nobody can find later, totals that look different on the other side, or an attachment that bounces.

This guide is about the sending side. It starts after the invoice is written. If you still need to write one, the freelance invoice template adds up the totals for you, and a free PDF invoice generator for freelancers explains what belongs on it. This is general information, not legal or tax advice.

Start from a finished invoice

There are three common ways to end up with an invoice file. Each has one thing to watch.

• From the PDFinish template. Fill it in and save it flattened, so your numbers become part of the page and cannot shift in your client's viewer.
• From a Word or Excel invoice. Use Save as PDF or Export inside that program. If you use Word to PDF or Excel to PDF here instead, note that those two tools send the file to our server, which converts it and deletes it when it finishes.
• From a photo or a scan. Avoid this if you can. A picture of a page cannot be searched, and your client cannot copy your payment details out of it. Type the invoice instead.

Send it in five steps

These steps use Fill PDF, which runs in your browser. The invoice, with your client's name and your payment details on it, is not uploaded.

1. Fill in the invoice and read it once from the top. Check the invoice number, the date, the client's name and the due date before anything else.
2. Check the maths. Pick two lines and work them out by hand. The template adds the totals as you type, but a wrong rate still gives a wrong total.
3. Save it flattened. A flattened copy is no longer editable, so nobody changes a number by accident, and it shows the same in every program.
4. Name the file with the client and the invoice number, such as Acme-2026-014.pdf. Skip words like final or v2.
5. Attach it to a short email. Put the invoice number and the amount due in the subject line, then say in a line or two what it is for and when it is due.

A short email to go with it

Keep the message plain. Something like this is enough: "Hi Sam, attached is invoice 2026-014 for the logo project. The amount due is in the subject line and the due date is at the top of the page. Payment details are at the bottom. Thank you." Repeat the key facts in the email, because some people pay straight from the message without opening the file.

Open it the way your client will

Before you send, open the saved file on your phone. Many clients read invoices on a phone, so this is the view that matters. Check that every line fits on the screen, that the total is visible and that the payment details can be selected and copied.

If you can, email the file to yourself first and open the attachment from your inbox. It takes a minute and shows you what the other side will see.

When the file is too big to attach

A typed invoice is small. Size trouble starts when you add a photo of your logo, send a scan, or join the invoice with receipts. Email services and client portals set their own limits, so read the number on the portal or ask your client.

Then use Compress PDF. Keep Balanced, which saves photos smaller and keeps text as text, and choose a size limit of 1, 2, 5 or 10 MB under Do you have a size limit? Skip Strong for invoices. It turns every page into a picture, so your client can no longer select your account number to copy it.

If you have supporting files, send one PDF instead of five attachments. Put the invoice first and the backup after it, and join them with Merge PDF.

Invoices with private details

An invoice carries your address and often your bank or payment details. If you want extra care for a particular client, lock the file with Password Protect PDF and send the password by another route, such as a text message. Nobody can recover a forgotten password, so keep the unlocked original.

Why an invoice does not land

• The client says the file is blank. It was saved fillable, and their viewer did not show your typed answers. Save it flattened and send it again.
• The email bounced. The file is bigger than the other side accepts. Compress it, or send the extras in a second message.
• The client cannot find it later. A file called invoice.pdf looks like every other invoice they get. Use the client name and number.
• The totals look wrong. A rate, a quantity or the tax rate was typed incorrectly. Fix it, save a new copy and tell the client which file replaces the old one.
• You sent a photo. A phone picture of a printed invoice is hard to read and cannot be searched. Send the PDF instead.

A worked example

A copywriter finishes a month of work for one client. She opens the template, types three lines of work and the tax rate, and checks that the total matches her own sum. She saves a flattened copy as Northfield-2026-021.pdf and opens it on her phone to see how it reads.

Then she emails it with the invoice number and the amount in the subject. The next month she copies the file, changes the number and the dates, and sends it again in a few minutes.

A short checklist

• Invoice number, dates and client name are correct.
• Totals match your own sum.
• Saved flattened, named with the client and number.
• Opened once on a phone.
• Small enough for the other side to receive.
• A saved copy for your records.

Filling in any template is free with no account, and your 2 free uses in total need no account either. More for self-employed work is on the freelancers page.