Expense claims, warranty returns and rent records all tend to end the same way: someone asks for "the receipts as one PDF". If your receipts live as twelve photos in your camera roll, that one request can eat half an hour. Here is the workflow I've settled on for doing it from a phone, with fewer rejected uploads and less re-shooting.

1. Shoot the receipt so it survives compression

Most claim portals and finance inboxes cap uploads somewhere between 1 and 5 MB, so your PDF will often be compressed. Thermal paper receipts are faint to begin with, and compression is where they turn unreadable. A few habits help a lot:

  • Flatten it first. Curled receipts throw shadows across the totals. Press it under a book for a minute or tape the corners down.
  • Use a dark, plain background. White receipt on a dark table gives the camera a clean edge and better exposure.
  • Light from the side, not above. Overhead light puts your phone's shadow right on the paper.
  • Fill the frame, then stop. Get close enough that the text is large, but keep all four corners visible. Reviewers want to see the merchant name, the date and the total in one shot.
  • Turn off the flash. Flash glare on glossy or thermal paper wipes out exactly the line you need.

If a receipt is long (fuel stations and supermarkets love these), take two overlapping photos rather than one tiny one. Two readable pages beat one illegible page.

2. Name and order before you convert

The order of pages in the PDF is the order a reviewer reads them in. Decide it before converting, not after:

  • Chronological works for trip expenses and monthly records.
  • Grouped by category (travel, meals, lodging) works when the claim form has separate lines.
  • Invoice first, then proof of payment works for warranty and refund requests.

Put the summary item first. If the claim form asks for a total, a reviewer who sees the biggest receipt on page one is less likely to bounce it back.

3. Merge the photos into one PDF

You don't need a scanner app with a subscription for this. Any converter that can merge several images and let you reorder them will do. The one thing I check now is where the conversion happens. Receipts carry card digits, addresses and sometimes names, and plenty of free converters upload every image to a server first.

I use jpgtopdf, a free JPG to PDF converter that runs in the browser, so the photos stay on the phone. You add the images from the gallery or the camera, drag them into order, pick a page size and convert. Whatever tool you pick, the steps are similar:

  1. Select all the receipt photos at once.
  2. Drag them into the order you decided above.
  3. Choose A4 (or Letter in the US) if the PDF might be printed, or "fit to image" if it's only going to be read on screen.
  4. Convert, then open the PDF once before sending it.

4. Hit the size limit without wrecking readability

If the merged file is too big, lower the quality one step at a time and re-check the faintest receipt each time. The total and the date on that receipt are your readability test. A few rules of thumb:

  • Change one setting at a time. Drop quality a notch, convert, check, and only then try the next step down.
  • Don't shrink the page size to save bytes. It makes text smaller without saving much. Lower the image quality instead.
  • Split rather than crush. If a portal allows several attachments, two clear PDFs are better than one blurry one.

5. Check before you hit send

Thirty seconds of checking saves a week of back-and-forth:

  • Every page is upright and in the order you intended.
  • The merchant, date and amount are readable on every page when you zoom to 100%.
  • Nothing extra slipped in (a screenshot, a photo of your desk).
  • The file name says what it is: 2026-10-expenses-travel.pdf beats document(3).pdf.

6. Keep the originals for a while

Thermal receipts fade, sometimes within months. Keep the photos as well as the PDF, at least until the claim is paid or the warranty period ends. A folder per month in your gallery or cloud storage is enough.

That's the whole routine: flatten, shoot on a dark background, order, merge, shrink carefully and check. If you have a trick for faded thermal receipts that I haven't covered, I'd like to hear it in the comments.