We do not provide DNS servers for your domains. Most hosting providers provide them free of charge. You can also use a free service such as xname.org.
You can modify the DNS servers of each domain purchased on Youdot at any time. The update is done within minutes after validation. Once the new DNS are published, however, there is still a delay corresponding to the time needed to purge the DNS cache.
As a reminder, it is imperative that your DNS configuration is correct and has knowledge of the domain, otherwise we will automatically cancel the modification. We do this to guarantee functional DNS. A DIG command allows you to check your DNS: https://toolbox.googleapps.com/apps/dig/#NS/