I know that an author can use a pen name/pseudonym instead of a true name when publishing the traditional way. This is done by signing contracts with the publisher/agent using the real name corresponding to the pen name.
How would this work if the author plans to publish him- or herself? If there are no contracts using the true name behind the author, is there a registration field with the ebook publishers/vanity publishers, or must you go to a lawyer to sign some statement/contract?
Unlike the other answers, let me try to give you a practical, nuts and bolt answer.
When you go to self-publish your book, either as an ebook (Amazon, Kobo, etc.) or print (Createspace, etc.) you are asked to give an author name. This field is not automatically filled based on your registered name, so you can fill in any name you want in the author field.
This name will show up when someone searches for your book on Amazon, for example. When it's time to get paid, the distributor (Amazon, Kobo) will look at your registered name and address (on your account) and send the money to that name.
So yeah, using the pen name when self publishing is extremely easy.
So yeah, using the pen name when self publishing is extremely easy.... not on the iBooksStore. Apple has draconian rules and are still operating on the 16th Century. New books are always created on the system using your full name, what is pretty much irritating. You will have to contact their support and spend hours trying to convince them. I was able to do convince them because I have had 16 books previously published in paper using my pseudonym in Europe and the US but new authors will probably suffer to convince them. Hello Apple, join the world on the 21st century.
Is your goal to actually hide your identity? Like you're advocating the violent overthrow of the government and you don't want the police to track you down? Or maybe more realistically, you're afraid your writing might interfere with business relationships, like you don't want co-workers to know that you're writing sex novels? Or is it that you think a pseudonym would help sell your book? Perhaps you think your real name doesn't sound cool enough, or your name sounds inconsistent with the type of book you're writing. Like, you want to publish a Chinese cook book and your real name is Patrick O'Malley?
What do you see as the problem? I can only think of two likely issues: 1. Establishing copyright. 2. Being able to receive and cash the royalty checks.
RE copyright: In the U.S., when you register your copyright there is a place on the form to say you're using a pseudonym. You can also give your real name if you want to, but you are not required to. If you do give your real name, it will be possible for people to find it by looking up the records at the copyright office. The duration of the copyright is different if you don't give your real name, because they then can't base it on when you die. See this link for more info.
RE royalty checks: Again, speaking for the U.S.: If you use a pseudonym, you can endorse a check with a pseudonym and then endorse it with your real name. I think that would be hard for an outsider to track down. Lots of places today use direct deposit, in which case I don't know exactly what information is sent to the bank. Anybody here know? Does the payer tell the bank, "this deposit is for Fred Smith, account number 12345"? Or do they just say "for account number 12345"? If they do give a name, does the bank compare it to the name on the account? In any case, if this was an issue, you could simply open a business account and have the deposits made in the name of the business. That's what I did for my second book anyway. If there was a crime involved I'm sure the police could track down the true owner of the account, but such information is generally confidential. Someone curious about the real author couldn't call the bank and ask who is authorized to withdraw money from the account. Well, they could ask, but the bank won't tell them.
You can put anything you want as the name on the front cover and the name listed as the author of the work. However, as the publisher of the work, it's recommended that you use your real name, as this will allow you to establish that you are in fact the owner of the rights to publish and use that work.
Another option is to establish yourself as doing business as your pseudonym. There are some pitfalls here, and you'll have to look up the laws in your jurisdiction to see exactly how you establish your pseudonym as the d.b
I only can give you a German perspective, but I could imagine that you face the same issues in other countries (like the US).
You can use a pen name as author, that is no problem at all. But as publisher it as a different matter.
Besides copyright and royalty payments (which shouldn't be a problem), there is the right of the readers to be considered. Because if the reader thinks there is something in the book worth suing you, then that should be possible for him.
E.g. if the reader thinks you have stolen his story, then he needs a real person he can sue, not a pseudonym. That's normally the publisher. So (in Germany) the real name of the responsible person at the publisher and a valid address (of a real building) must be provided in the book. If you are a self-publisher then that would be you and your home address (if you do not have an office for your self-publishing "company" somewhere else).
In the U.S. the real name is available from either the copyright office or Amazon in a legal dispute. Using a publishing name doesn't change that.
Also, here only the account number is used for direct deposit.
