To change the nameservers for your domain, you will need to do the following:
1.Sign in to your Namecheap account.
2.Select Domain List from the left sidebar and click the Manage button next to your domain:
3.Find the Nameservers section and select your preferred option from the drop-down menu.
4.You should choose from four possible options:
CustomDNS – Add the Nameservers Provided by us
5.Click on the green checkmark to save the changes: