Add default domain

Please let know how to add the azure domain being indexed by google in .net core.

This is code please let me know how to add this and which file

<rewrite>      
  <outboundRules>
    <rule name="Noindex Domains">
      <match serverVariable="RESPONSE_X_Robots_Tag" pattern=".*" />
      <conditions>
        <add input="" pattern="^(domainA.azurewebsites.net|domainB.azurewebsites.net)$" />
      </conditions>
      <action type="Rewrite" value="NOINDEX, NOFOLLOW"/>
    </rule>
  </outboundRules>
</rewrite>