Selling a book directly is the part nobody writes about, because it sounds trivial next to writing one. It is trivial, right up until the first buyer emails to say the file will not open on their phone, or that the download link expired before they got to it, or that they want the version with the corrected chapter nine.
All three are avoidable with decisions made before the first sale.
Which files to send
Send both, in one download. They are not competing formats; they are for different reading situations, and buyers do not know in advance which one they will want.
| Format | What it is for | Include? |
|---|---|---|
| Reading on a computer, and printing | Always | |
| EPUB | Phones, tablets, e-readers, reflowing to any screen | Always |
| MOBI / AZW3 | Old Kindle devices | No — Amazon retired it; modern Kindles take EPUB |
| DOCX | Only if the buyer is meant to edit it | Rarely, and only for templates |
The MOBI row catches people out because so much older advice still lists it. Amazon's Send to Kindle now accepts EPUB directly, so an EPUB covers Kindle owners as well. The difference between the two main formats is worth understanding, but the delivery decision is simply: ship both.
How to actually deliver it
Use a platform that takes the payment and serves the file in the same transaction. The buyer pays, the download appears, and a receipt with a permanent link arrives by email. Anything with more steps than that loses people between the card and the file.
- Do not email attachments. Mail servers reject attachments over 10 to 25MB, and an unexpected file from an unknown sender is the exact shape of a phishing email. It will be filtered.
- Do not use a raw cloud-drive link. Shared folders get moved, permissions lapse, and a buyer who returns in a year finds nothing.
- Do not expire links quickly. A 24-hour download window exists to prevent sharing and mostly prevents buying. People purchase on a phone and download on a laptop three days later.
- Do give a permanent library. A page the buyer can log back into is what makes updates possible later, and it is why platform delivery beats a one-off link.
A zip file is the wrong answer too, even though it bundles both formats neatly: phones and tablets handle zips badly, and the buyer most likely to be inconvenienced is the one reading on the device they bought it on.
What about DRM?
For a direct sale, skip it. This is not an ideological position — it is what the mechanics actually deliver.
- It does not work. Every consumer ebook DRM scheme has been broken, and stripping it takes a determined reader about four minutes. The people who would share the file are unaffected.
- It punishes the honest buyer. DRM ties a file to an account or an app, so the person who paid discovers their book will not open on their new e-reader.
- It costs you. Implementing it means a third-party service, a fee, and support tickets from people who cannot open what they bought.
The thing that genuinely reduces casual sharing is social: put the buyer's name and order number on the copyright page or in the footer. It costs nothing, it is invisible to anyone reading normally, and it makes uploading the file feel personal in a way that a technical lock never does. Most direct sellers find that a fair price, a good product and an easy download do more than any protection scheme.
Updating a book people already bought
This is the real advantage of selling directly, and almost nobody uses it. A digital book is not finished at publication — you will find typos, a link will die, a chapter will need revising. On a platform with a buyer library, you replace the file and everyone who ever bought it has the new one.
What makes that painless is having a single source the whole book is built from. If your PDF was hand-corrected in one application and your EPUB in another, a one-line fix in chapter nine is now two edits, two exports and a real chance of the formats diverging. If both files export from the same Markdown, it is one edit and one export.
- Version the book, visibly. A line on the copyright page: "Second edition, March 2027." Buyers need to know which one they have.
- Keep a short changelog at the back for anything more than typos. It is two paragraphs and it makes a re-download feel worth doing.
- Email the list when it is substantial. Not for a typo. For a new chapter, absolutely — it is the cheapest goodwill available to a self-publisher.
The small things that prevent support emails
| Problem | Prevention |
|---|---|
| "It will not open on my Kindle" | One line in the receipt: email the EPUB to your Send to Kindle address |
| "The download link is dead" | Permanent library links, not expiring ones |
| "I cannot find the file" | Descriptive filenames with title and author |
| "Which file do I want?" | A one-line README, or name them clearly: ...-print.pdf, ...-ereader.epub |
| "The images look wrong" | Test the EPUB on a real phone before selling it, not only in a desktop reader |
| "I bought it twice by accident" | Refund immediately and without discussion. It costs less than the exchange |
The testing row is the one worth doing properly. An EPUB that validates can still look wrong on a device — validation catches structural faults, not design ones. Open it on a phone, and on the oldest e-reader you can borrow, before anyone pays for it.
None of this is complicated, and all of it is decided before your first sale rather than during it. Export both formats from one source, sell through something that hands over the file the moment the payment clears, skip the DRM, and keep the buyers' library live so the second edition reaches everyone. The sample book is what the PDF half of that looks like finished.