Like it or not, current and future authors, CreateSpace, the self-publishing platform that was acquired by Amazon over ten years ago, is merging with Amazon’s Kindle Direct Program.
If you are already publishing with CreateSpace, you have probably received an email telling you how to move your account. As KDP’s information page notes, you can expect some differences if you decide to publish with KDP.
Apparently, phone service will not be available at KDP (as it was with CreateSpace) if you have problems or questions. (If that is something that is important to you, you may wish to consider one of the other author publishing services, such as IngramSpark. You may, however, have to pay title setup fees, and you may also incur additional charges if you make changes to your files after they have been submitted to IngramSpark.)