The rule below will redirect all users connecting to the webpage to a secure connection (https) on the same domain.

<rewrite>
   <rules>
      <rule name="Redirect to https">
         <match url="(.*)" />
         <conditions>
            <add input="{SERVER_PORT}" pattern="443" negate="true" />
         </conditions>
         <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" />
      </rule>
   </rules>
</rewrite>