A domain is a service that allows you to reserve and use a specific set of characters in the selected domain zone. After registration you can use this domain for website and create an email.
Each domain is unique. In other words, if you made a misprint when registering a domain and placed an order, then you will get just another domain.
Change or return the domain name after it is already registered is not possible.
If you made an order, paid for it and found out that you made a mistake - first of all check the "Invoices to pay" section. If you see that the invoice is not yet paid - click on the invoice number, make sure it is an invoice for paying the mistaken domain and cancel it by clicking the "Cancel invoice" button.
In case when the payment system has not transferred funds yet, the cancellation of the invoice will allow you not to register this particular wrong domain. When the invoice is closed, funds will be added to your personal NIC.UA account and you can pay with them for the correct domain.