Any company you've registered your domain with will be able to configure its DNS Records.
Many providers offer a control panel that can be used to configure them autonomously.
The procedure is simple and can be requested to the provider itself via email.
Generally the best configuration is the one that follows, since it provides the automatic IP address update in the event of future changes made by
Configure the records for domainnname.com as follows:
C-Name record for www to point to ea26.com
MX record for domainnname.com to point to ea26.com